CYCLOPROPENIUM POLYMERS AND METHODS FOR MAKING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present invention claims benefit to U.S. provisional application serial no. 61/677,837 filed July 31 , 2012, the entire contents of which are incorporated by reference.

FIELD OF INVENTION

[0002] The present invention provides, inter alia, processes for incorporating a cyclopropenium ion into a polymeric system, for making cross-linked polymers, linear polymers, and dendritic polymers, as well as for incorporating a cyclopropenium ion onto a preformed polymer. Further provided are substrates made from such processes.

BACKGROUND OF THE INVENTION

[0003] The ability to incorporate stable ionic moieties on linear, branched, dendritic, and cross-linked polymeric systems has led to the development of materials that can be employed in a wide variety of applications, such as water purification, drug delivery, gene therapy, antimicrobial coatings, ion transporting membranes, and as cell substrates, among others. For example, water desalination membranes are currently being synthesized by cross-linking polymerization of 1 ,3- benzenediamine and trimesoyl chloride, to yield a polyelectrolyte. Other materials, such as electrostatic layers have also been evaluated. Starpharma has developed dendritic polyelectrolytes based on polyamidoamine (PAMAM) as HIV prevention drugs and for drug delivery. Drug delivery vectors containing guanidine have also been shown to be effective mimics of cell-penetrating peptides.

[0004] Cationic polymers are desirable for many reasons, but available materials suffer from a number of limitations, such as pH sensitivity, difficulty of synthesis, or lack of variability. For example, in water purification membranes, currently available materials lack tunable mechanical properties and can be brittle. Furthermore, the chemistry is more difficult to manage due to the fact that the acid chlorides that are currently used are water sensitive, and must be processed in dry conditions.

[0005] Accordingly, there is a need for, inter alia, stable ionic moieties on linear, branched, dendritic, and cross-linked polymeric systems that are simple to prepare, are broadly tunable in terms of their properties, and are stable across a wide range of pH levels. The present invention is directed to meeting these and other needs.

SUMMARY OF THE INVENTION

[0006] The inventors have discovered the ability to incorporate a cyclopropenium cation (CPC) into polymeric architectures and modular platforms and to exploit these materials in applications where stable polycationic species are desired. The CPC is an esoteric functional group in materials chemistry. It has the unique ability to remain positively charged at high pH, a property that is difficult to match with any other functional group. Conventional materials having ionic moieties integrated into polymeric systems traditionally have used basic units that are protonated (such as amines), and these materials tend to lose their charge at pHs above 7. Due to the loss of charge at physiological conditions, such conventional materials are less efficient in their respective applications, including but not limited to desalinization, drug delivery, surface coatings, antimicrobial coatings, etc. In contrast, the stable polycationic materials of the present invention are simple to prepare, are broadly tunable in terms of their properties, and are stable in pHs ranging from 0 to greater than 14. Thus, the stable polycationic materials of the present invention will provide unparalleled performance for drug delivery, DNA binding, desalinization, and myriad other applications.

[0007] In this regard, one embodiment of the present invention is a process for incorporating a cyclopropenium ion into a polymeric system. This process comprises contacting a functionalized cyclopropenium ion with a functionalized compound capable of reacting with the functional group of the cyclopropenium ion for a period of time and under conditions suitable for the functionalized cyclopropenium and the functionalized compound to react and form a polymeric system that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0008] Another embodiment of the present invention is a process for making a cross-linked polymer. This process comprises contacting an alkene functionalized cyclopropenium ion with a polymer comprising a pendant thiol group, for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the polymer to react and form a cross-linked polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0009] Yet another embodiment of the present invention is a process for making a cross-linked polymer. This process comprises contacting a thiol functionalized cyclopropenium ion with a functionalized compound comprising an alkene group, for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the functionalized compound to react and form a cross- linked polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0010] A further embodiment of the present invention is a process for making a linear polymer. This process comprises contacting a functionalized cyclopropenium ion with a polymerizing agent for a period of time and under conditions suitable for the functionalized cyclopropenium ion to react and to form a linear polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0011] An additional embodiment of the present invention is a process for incorporating a cyclopropenium ion onto a preformed polymer. This process comprises contacting a cyclopropenium ion functionalized to participate in a click reaction with a preformed polymer backbone having a pendant group that is functionalized with a complementary group suitable for participating in a click reaction with the cyclopropenium ion for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the preformed polymer to react via a click chemistry mechanism and form a polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0012] Another embodiment of the present invention is a process for making a dendritic polymer. This process comprises the steps of:

a. providing a first functionalized compound comprising a cyclopropenium ion, which has a reactive group at each position of the ring; and b. grafting a second functionalized compound onto each reactive group of the first functionalized compound such that chemical bonds are formed between the first functionalized compound and the second functionalized compound at the reactive groups, the second functionalized compound including reactive groups capable of forming bonds with the reactive groups on the cyclopropenium ion, and wherein the bonds are formed through a click chemistry mechanism.

[0013] An additional embodiment of the present invention is a stable, polycationic compound made by any process disclosed herein.

[0014] A further embodiment of the present invention is a polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH, the polymer having the structure:

wherein

X-i-2 are independently selected from the group consisting of CI, N, and any other atom suitable for participating in the process;

R-i-2 are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d.-ioalkoxy, C _2- ioalkenyloxy, C _2- ioalkynyloxy, Ci.i ₀ alkyl, C _3- iocycloalkyl, C _2- ioalkenyl, C _3- iocycloalkenyl, C _2- i ₀ alkynyl, halogen, aryloxy, heteroaryloxy, C _2- - _l oalkoxycarbonyl, d.-ioalkylthio, C _2- i ₀ alkenylthio, C _2- i ₀ alkynylthio, Ci.i ₀ alkylsulfonyl, d-ioalkylsulfinyl, aryl-d-ioalkyl, heteroaryl-Ci-ioalkyl, aryl-Ci-ioheteroalkyl, heteroaryl-Ci-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein Ri and R ₂ are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R ₂ are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, C ₂ - ₆ alkenyl, C ₂ - ₆ alkynyl, aryl, Ci- ₆ alkoxy, C ₂ - ₆ alkenyloxy, C ₂ -6alkynyloxy, aryloxy, C ₂ -6alkoxycarbonyl, Ci-6alkylthio, d- ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, d- ₆ alkylamino, Ci-6dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus; represents a suitable linking group; and

n is an integer.

[0015] Another embodiment of the present invention is a cross-linked polymer. This polymer comprises a stable cyclopropenium cation that remains positively charged at a high pH, the cross-linked polymer having the structure:

(22a) wherein

( ^■ I represents a suitable linking group; and

polymer is any polymer that can be bonded to the cyclopropenium ion.

[0016] An additional embodiment of the present invention is a dendrimer having (1 ) a cationic core comprising a tri-functional cyclopropenium monomer and (2) at least two ordered dendritic core branches which (a) are covalently bonded to the cationic core, (b) extend through at least two generations, and (c) have at least 3 terminal groups per core branch.

[0017] A further embodiment of the present invention is a substrate. This substrate comprises a stable, polycationic compound made by any process disclosed herein.

[0018] Another embodiment of the present invention is a support coated with any substrate disclosed herein for use in a water purification system.

[0019] Additional embodiments of the present invention include an antimicrobial coating, an ion-transport membrane, and a cell support, each of which comprises a substrate as disclosed herein.

[0020] Yet another embodiment of the present invention is a drug delivery vehicle comprising a stable cationic dendritic polymer made according to any method disclosed herein.

[0021] A further embodiment of the present invention is a gene therapeutic vector comprising a stable cationic dendritic polymer made according to any method disclosed herein.

[0022] Another embodiment of the present invention is a process for incorporating a cyclopropenium ion into a polymeric system. This process comprises contacting a functionalized cyclopropene with a functionalized compound capable of reacting with the functionalized cyclopropene for a period of time and under conditions suitable for the functionalized cyclopropene and the functionalized compound to react and form a polymeric system that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 shows a schematic representation of clicking the cyclopropenium groups onto a preformed polymer.

[0024] Figure 2 shows a schematic representation of forming dendrimers from tri-functional monomers.

[0025] Figure 3 shows an image of a cross-linked polymer made according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] One embodiment of the present invention is a process for incorporating a cyclopropenium ion into a polymeric system. This process comprises contacting a functionalized cyclopropenium ion with a functionalized compound capable of reacting with the functional group of the cyclopropenium ion for a period of time and under conditions suitable for the functionalized cyclopropenium and the functionalized compound to react and form a polymeric system that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0027] In the present invention "incorporating" means to reset and form a bond between, e.g., a cyclopropenium ion and a preformed or currently forming polymeric system. Preferably, the bond formed between the cydopropenium and the polymeric system is covalent.

[0028] As used herein, the term "cydopropenium ion" means a charged species derived from a cyclopropene having the structure:

(cyclopropene)

[0029] Derivatives of cyclopropenes, such as tetrachlorocyclopropene, are commercially available from e.g., Sigma Aldrich (St. Louis, MO). As is also known, cydopropenium ions are highly geometrically strained, but they are stabilized due to aromaticity. Various methods for making cydopropenium ions are also known. See, e.g., Wilcox et al., 1980; Yoshida, 1973.

[0030] In one aspect of the present embodiment, the polymeric system may be any polymer containing agents into which a stable cydopropenium cation that remains positively charged at a high pH may be integrated. As used herein, a "polymeric system" means a macromolecule having repeating sub-units that are connected by covalent bonds. Non-limiting examples of polymeric systems include linear polymers, branched polymers, cross-linked polymers, and dendritic polymers. "Linear polymers" mean polymers whose subunits are arranged in a linear chain. "Branched polymers" mean polymers whose chains have branching points that connect two or more chain segments. Branching generally occurs by the replacement of a substituent, e.g., a hydrogen atom, on a monomer subunit, by another covalently bonded chain of that polymer or by a chain of another type. "Cross-linked polymers" mean branched polymers in which adjacent long chains are joined to one and another at various positions along their lengths. The cross-linking creates greater rigidity and stability. "Dendritic polymers" or "dendrimers" mean a polymer having a polyvalent core that is covalently bonded to at least two ordered dendritic (tree-like) branches which extend through at least two generations. Dendrimers thus have a starburst structure. As an exemplary illustration only, an ordered second generation dendritic branch is depicted by the following configuration:

wherein "a" represents the first generation and "b" represents the second generation. An ordered, third generation dendritic branch may be depicted by the following exemplary configuration:

wherein "a" and "b" represent the first and second generation, respectively, and "c" represents the third generation. A primary characteristic of the ordered dendritic branch which distinguishes it from conventional branches of conventional polymers is the uniform or essentially symmetrical character of the branches as is shown in the foregoing exemplary illustrations. In addition, with each new generation, the number of terminal groups on the dendritic branch is an exact multiple of the number of terminal groups in the previous generation. In the present invention, the number of generations is unlimited. Preferably, however, there are from about 1 -1 ,000 generations, such as from about 1 -500, 1 -250, 1 -100, 1 -50, 1 -25, 1 -15, 1 -10, 1 -5, including 1 -3 generations. The number of generations will be determined based on the particular end use of the final product.

[0031] As used herein, the term "functionalized" with reference to the cyclopropenium ion and the compound means possessing a functional group, which is an atom, or a group of atoms that has similar chemical properties whenever it occurs in different compounds. The respective functional groups, under certain suitable conditions defined herein, react to form the polymeric system.

[0032] Functional groups include without limitation, alkoxy, alkoxycarbonyl, alkyl, alkenyl, alkenyloxy, alkenylthio, alkylamino, alkylsulfinyl, alkylsulfonyl, alkylthio, alkynyloxy, alkynylthio, amino, amido, aryl, aryloxy, aryl-alkyl, aryl-heteroalkyl, azide, carbocycle, carbonyl, carboxy, carboxylate, cyano, cycloalkyl, cycloalkenyl, ether, halo, heteroaryl, heteroaryloxy, heteroaryl-alkyl, heteroaryl-heteroalkyl, heteroalkyl, heteroaromatic, heterocycle, hydrocarbyl, hycroxyalkyl, hydroxyl, imino, nitro, polycycle, oxo, sulfate, sulfinyl, sulfonyl, thiol, thioalkyl, and thiono groups.

[0033] As used herein, conditions "suitable" for the functionalized cyclopropenium and the functionalized compound to react and form a polymeric system are as exemplified herein and may also include those conditions disclosed by, e.g., Campos, 2008a and Campos 2008b. Parameters that may be varied to achieve such "suitable" conditions include the concentration of the reactants, the duration of the reaction, the temperature of the reaction, the selection/use of solvent(s), and other reagents for isolating or otherwise purifying the products. Non- limiting exemplary "conditions suitable" for this process are disclosed, e.g., in the Examples herein and may be further apparent to those skilled in the art in view of the disclosures herein.

[0034] In the present invention, a "stable" cyclopropenium cation means a cyclopropenium group with a positive charge that is not particularly reactive under anticipated conditions of use, and retains its useful properties on the timescale of its expected usefulness. For example, a stable cyclopropenium cation would not undergo ring opening reactions under normal conditions.

[0035] In the present invention, the polymeric system formed by contacting a functionalized cyclopropenium ion with a functionalized compound includes a stable cyclopropenium cation that is positively charged preferably over a large pH range such as, e.g., from 0 to greater than 14. Preferably, such cyclopropenium cation remains positively charged at a high pH, such as, e.g., a pH above 7, such as 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 1 1 , 1 1 .5, 12, 12.5, 13, 13.5, or 14. More preferably, the cyclopropenium cation incorporated into the polymeric system remains positively charged in a pH range from 8 to 13.

[0036] In another aspect of this embodiment, the functionalized cyclopropenium ion is a compound of formula (100):

wherein Χ-ι-3 are independently selected from the group consisting of CI, N and any other atoms suitable for participating in the process; and

Ri _-4 are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d-ioalkoxy, C2-ioalkenyloxy, C2-ioalkynyloxy, d-ioalkyl, C3-iocycloalkyl, C2-ioalkenyl, C3-iocycloalkenyl, C2-ioalkynyl, halogen, aryloxy, heteroaryloxy, C2- ioalkoxycarbonyl, Ci-ioalkylthio, C2-ioalkenylthio, C2-ioalkynylthio, d-ioalkylsulfonyl, Ci-ioalkylsulfinyl, aryl-Ci-ioalkyl, heteroaryl-Ci-ioalkyl, aryl-Ci-ioheteroalkyl, heteroaryl-Ci-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein Ri and R2 or R ₃ and R ₄ are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R2 are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, C2-6alkenyl, C2-6alkynyl, aryl, d- ₆ alkoxy, d-ealkenyloxy, d-ealkynyloxy, aryloxy, d-ealkoxycarbonyl, d-6alkylthio, d- ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, d- ₆ alkylamino, Ci-6dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus.

[0037] As used herein, atoms "suitable for participating in the process" means atoms that do not interfere with the incorporation of a cyclopropenium ion into a polymeric system. Besides N and CI, non-limiting examples of other atoms that are suitable for participating in the process may include halogens such as F, Br, and I.

[0038] Preferably, the functionalized cyclopropenium ion is selected from the group consisting of:

( ⁶ ) and W optionally together with an appropriate counter ion. Such counter ions may be any negatively charged ion, including without limitation, chloride, bicarbonate, phosphate, and sulfate ions.

[0039] In another preferred embodiment, the functionalized cyclopropenium ion is selected from the group consisting of:

(6) _and (4)

wherein

Ri _-4 are independently selected from the group consisting of .

[0040] In yet another preferred embodiment, the functionalized cyclopropenium ion is selected from the group consisting of:

(6) and (4)

wherein

Ri- are independently selected from the group consisting of R , wherein R is any group that is suitable for participating in the process of incorporating the cyclopropenium ion into the polymeric system; and combinations thereof.

[0041] As used herein, a group that is "suitable for participating in the process of incorporating the cyclopropenium ion into the polymeric system" is any chemical group that can be stably attached to the cyclopropenium ion in the polymeric system. Such suitable groups are selected from moieties that are not overly bulky, such as, e.g., hydrogen and methyl, so as to minimize crowding around the cyclopropenium ion.

[0042] In yet another preferred embodiment, the functionalized cyclopropenium ion is:

(21)

[0043] additional preferred embodiment, the functionalized cyclopropenium ion is:

(23)

[0044] In a further preferred embodiment, the functionalized cyclopropenium ion is:

[0045] In another preferred embodiment, the functionalized cyclopropenium ion is:

[0046] In a further aspect of this embodiment, the functionalized compound capable of reacting with the functional group of the cyclopropenium ion is a polymer selected from the group consisting of a linear polymer, a branched polymer, a cross- linked polymer, and a dendritic polymer. Preferably, the polymer is a homopolymer or a heteropolymer. As used herein, a "homopolymer" is a polymer that contains only a single type of repeating sub-unit. A "heteropolymer" or "copolymer" is a polymer containing a mixture of repeating sub-units. Heteropolymers include random copolymers, block copolymers, and graft copolymers.

[0047] As used herein, a "random copolymer" means a copolymer in which the probability of finding a given monomeric unit at any given site in the chain is independent of the nature of the adjacent units.

[0048] As used herein, a "block copolymer" means a copolymer containing blocks or segments of different polymerized monomers. [0049] As used herein, a "graft copolymer" means a copolymer with one or more species of segments connected to the backbone as side chains, these side chains having different composition or sequence distribution from the backbone. The term "backbone" as used herein refers to that portion of the polymer which is a continuous chain. The term "side chain" refers to portions of the polymer that append from the backbone.

[0050] In another aspect of this embodiment, the backbone of the polymer comprises a group selected from the group consisting of ethylene, propylene, styrene, (meth)acrylate, vinyl chloride, urethane, ethylene terephthalate, ester, amide, norbornene, silicon, oxygen, and combinations thereof.

[0051] Another embodiment of the present invention is a process for making a cross-linked polymer. This process comprises contacting an alkene functionalized cyclopropenium ion with a polymer comprising a pendant thiol group, for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the polymer to react and form a cross-linked polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0052] In one aspect of this embodiment, the process is carried out according to the following reaction:

[0053] In this reaction, n may be any integer. Preferably, n is from 1 to 10 ¹⁰ , such as from 1 to 10 ⁷ , 1 to 10 ⁵ , 1 to 1000, 1 to 500, 1 to 50, and 1 to 10. Selection of the size of the polymer will be driven by the desired functions of the cross-linked polymer.

[0054] The initiator in this reaction is preferably, a radical initiator that is activated by heat or light, such as, e.g., phenylacetophenone (DMPA), azobisisobutyronitrile (AIBN), 4,4'-azobis(4-cyanovaleric acid), 1 ,1 '- azobis(cyclohexanecarbonitrile), 2-benzyl-2-(dimethylamino)-4'- morpholinobutyrophenone, 4'-tert-butyl-2',6'-dimethylacetophenone, 2,2- diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, diphenyl(2,4,6- trimethylbenzoyl)phosphine oxide/2-hydroxy-2-methylpropiophenone, 4'- ethoxyacetophenone, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, 1 - hydroxycyclohexyl phenyl ketone, 2-hydroxy-4'-(2-hydroxyethoxy)-2- methylpropiophenone, 2-hydroxy-2-methylpropiophenone, 2-methyl-4'-(methylthio)- 2-morpholinopropiophenone, 4'-phenoxyacetophenone, benzoin, 4,4'- dimethoxybenzoin, 4,4'-dimethylbenzil, benzophenone-3,3',4,4'-tetracarboxylic dianhydride, 4-benzoylbiphenyl, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis[2-(1 - propenyl)phenoxy]benzophenone, 4-(diethylamino)benzophenone, 4,4'- dihydroxybenzophenone, 4-(dimethylamino)benzophenone, 3,4- dimethylbenzophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 2- methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, methyl benzoylformate, michler's ketone, bis(4-tert-butylphenyl)iodonium perfluoro-1 - butanesulfonate, bis(4-tert-butylphenyl)iodonium p-toluenesulfonate, bis(4-tert- butylphenyl)iodonium triflate, boc-methoxyphenyldiphenylsulfonium triflate, (4- bromophenyl)diphenylsulfonium triflate, (tert-butoxycarbonylmethoxynaphthyl)- diphenylsulfoniunn triflate, (4-tert-butylphenyl)diphenylsulfonium triflate, diphenyliodoniunn hexafluorophosphate, diphenyliodoniunn nitrate, diphenyliodoniunn perfluoro-1 -butanesulfonate, diphenyliodoniunn p-toluenesulfonate, diphenyliodoniunn triflate, (4-fluorophenyl)diphenylsulfonium triflate, n-hydroxynaphthalimide triflate, n- hydroxy-5-norbornene-2,3-dicarboximide perfluoro-1 -butanesulfonate, (4- iodophenyl)diphenylsulfonium triflate, (4-methoxyphenyl)diphenylsulfonium triflate, 2- (4-methoxystyryl)-4,6-bis(trichloromethyl)-1 ,3,5-triazine, (4- methylphenyl)diphenylsulfonium triflate, (4-methylthiophenyl)methyl phenyl sulfonium triflate, 1 -naphthyl diphenylsulfoniunn triflate, (4-phenoxyphenyl)diphenylsulfonium triflate, (4-phenylthiophenyl)diphenylsulfonium triflate, t arylsulfonium hexafluoroantimonate, tharylsulfonium hexafluorophosphate, triphenylsulfonium perfluoro-1 -butanesufonate, triphenylsulfonium triflate, tris(4-tert- butylphenyl)sulfonium perfluoro-1 -butanesulfonate, tris(4-tert-butylphenyl)sulfonium triflate, 1 -chloro-4-propoxy-9h-thioxanthen-9-one, 2-chlorothioxanthen-9-one, 2,4- diethyl-9h-thioxanthen-9-one, isopropyl-9h-thioxanthen-9-one, 10- methylphenothiazine, thioxanthen-9-one, persulfate, tert-butyl hydroperoxide, tert- butyl peracetate, cumene hydroperoxide, 2,5-di(tert-butylperoxy)-2,5-dimethyl-3- hexyne, dicumyl peroxide, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,4- pentanedione peroxide, 1 -bis(tert-butylperoxy)-3, 3, 5-trimethylcyclohexane, 1 ,1 - bis(tert-butylperoxy)cyclohexane, 1 ,1 -bis(tert-amylperoxy)cyclohexane, benzoyl peroxide, 2-butanone peroxide, tert-butyl peroxide, di-tert-amyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy 2-ethylhexyl carbonate, tert- butyl hydroperoxide, and lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) (Fairbanks et al., 2009). [0055] Yet another embodiment of the present invention is a process for making a cross-linked polymer. This process comprises contacting a thiol functionalized cyclopropenium ion with a functionalized compound comprising an alkene group, for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the functionalized compound to react and form a cross- linked polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0056] In one aspect of this embodiment, the process is carried out according to the following reaction:

[0057] In this embodiment, "n", "initiator", and "polymer" are as disclosed above.

[0058] Another embodiment of the present invention is a process for making a linear polymer. This process comprises contacting a functionalized cyclopropenium ion with a polymerizing agent for a period of time and under conditions suitable for the functionalized cyclopropenium ion to react and to form a linear polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH. [0059] In this embodiment, a "polymerizing agent" is a substance that facilitates the formation of covalent bonds among monomers to form polymers. Polymerizing agents include radical initiators, Reversible Addition-Fragmentation chain Transfer (RAFT) agents, and catalysts for click chemistry. Radical initiators are as disclosed above. RAFT agents include without limitation, pentamethyldiethylenetriamine (PMDETA), dithioesters dithiocarbamates, trithiocarbonates, and xanthates. Catalysts for click chemistry include without limitation Cu(l).

[0060] In one aspect of this embodiment, the process further comprises contacting the functionalized cyclopropenium ion with a monomer suitable for forming a copolymer with the functionalized cyclopropenium ion. In the present invention, a suitable monomer is one that will not interfere with the reaction in a substantive way and that provides a desired attribute as a part of the copolymer. Representative non-limiting examples of a suitable monomer in this reaction include vinyl monomers, pyrolyzates, alcohols, phenols, carboxylic acids, and their salts, esters, anhydrides, amides, hydrazides, urethanes, cyanates, fulminates, heterocycles, amino, and thiocarboxylic acids, and sulphonamides.

[0061] In another aspect of this embodiment, the process is carried out according to the following reaction:

wherein

is any suitable polymer backbone;

X-i-3 are independently selected from the group consisting of CI, N, and any other atom suitable for participating in the process;

Ri- are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d.-ioalkoxy, C _2- ioalkenyloxy, C _2- ioalkynyloxy, Ci.i ₀ alkyl, C _3- iocycloalkyl, C _2- ioalkenyl, C _3- iocycloalkenyl, C _2- i ₀ alkynyl, halogen, aryloxy, heteroaryloxy, C _2- i ₀ alkoxycarbonyl, d.-ioalkylthio, C _2- i ₀ alkenylthio, C _2- i ₀ alkynylthio, Ci.i ₀ alkylsulfonyl, Ci.i ₀ alkylsulfinyl, aryl-d.-ioalkyl, heteroaryl-Ci.i ₀ alkyl, aryl-Ci.i ₀ heteroalkyl, heteroaryl-Ci-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein R and R ₂ or R ₃ and R are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R ₂ are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, C _2-6 alkenyl, C _2-6 alkynyl, aryl, d. ₆ alkoxy, C _2-6 alkenyloxy, C _2-6 alkynyloxy, aryloxy, C _2-6 alkoxycarbonyl, Ci _-6 alkylthio, Ci_ ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, Ci_ ₆ alkylamino, Ci _-6 dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus, wherein one of R3 or R is a group that forms a polymer backbone when contacted with the polymerizing agent; and

A is selected from the group consisting of:

[0062] The polymerizing agent is as disclosed above. Preferably, the polymerizing agent is DMPA or AIBN.

[0063] In this aspect of the present invention, the length of the polymer backbone is not critical and is readily determined and/or modified according to the end use of the linear polymer. Thus n may be any positive integer. For example, n may vary between 1 -1 ,000,000, such as 1 -500,000, or 1 -250,000, or 1 -100,000, or 1 - 50,000, or 1 -25,000, or 1 -10,000, or 1 -1 ,000, or 1 -500, or 1 -250, or 1 -100, or 1 -50, or 1 -25, or 1 -10, or 1 -5.

[0064] Preferably, the backbone of the polymer is selected from the group consisting of polymers based on styrene, (meth)acrylate, norbornene, and combinations thereof.

[0065] In another preferred embodiment, R-i and R ₂ are independently selected from the group consisting of:

and combinations thereof.

[0066] In an additional preferred embodiment, X ₃ R ₃ R is selected from the group consisting of:

and combinations thereof.

[0067] An additional embodiment of the present invention is a process for incorporating a cyclopropenium ion onto a preformed polymer. This process comprises contacting a cyclopropenium ion functionalized to participate in a click reaction with a preformed polymer backbone having a pendant group that is functionalized with a complementary group suitable for participating in a click reaction with the cyclopropenium ion for a period of time and under conditions suitable for the functionalized cyclopropenium ion and the preformed polymer to react via a click chemistry mechanism and form a polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH. [0068] In the present invention, a "prefornned polymer" is intended to include any polymer suitable for participating in a click chemistry reaction with a suitably functionalized cyclopropenium ion as disclosed in more detail herein. Typically, the polymer is formed prior to the click reaction. The preformed polymer contains one or more pendant groups, which are able to react in a click chemistry reaction with the functionalized cyclopropenium as set forth in more detail below. Non-limiting examples of functionalized groups for the cyclopropenium ion and the preformed polymers are alkynes, azides, thiols, enes, epoxides, aziridines, aziridinium ions, aldehydes, and aminooxy groups.

[0069] The reaction time and conditions for the click chemistry will depend on the particular functional groups used and other desired properties and are well within the skill of the art to determine. Representative non-limiting reaction times and conditions are set forth in more detail below and in the Examples.

[0070] As used herein, a "click" reaction means a chemical reaction in which small modular components are joined together to form a larger molecule, are easy to perform, and give rise to their intended products in very high yields with little or no byproducts. Many click components are derived from alkenes and alkynes, and most click reactions involve the formation of carbon-heteroatom (mostly N, O, and S) bonds. Click reactions are usually fusion processes (leaving no byproducts) or condensation processes (producing water as a byproduct).

[0071] Perhaps the most famous of click reactions is the Huisgen 1 ,3-dipolar cycloaddition of alkynes and azides to yield 1 ,2,3-triazoles, which reaction is accelerated by copper(l) catalysis (Kolb et al., 2001 ). This reaction requires no protecting groups, and proceeds with extremely high yield and selectivity for the 1 ,4- disubstituted 1 ,2,3-triazole (anti-1 ,2,3-triazole). For a detailed review of the mechanistic aspects of this reaction, see, e.g., Bock et al., 2006.

[0072] Another example of a click reaction is the thiol-ene reaction involving the addition of a S-H bond across a double or triple bond by either a free radical or ionic mechanism. The reaction product is an alkenyl sulfide. For a review, see, e.g., Hoyle et ai, 2010.

[0073] Other non-limiting examples of click reactions include nucleophilic ring opening reactions, such as the opening of epoxides, aziridines, and aziridinium ions; non-aldol carbonyl chemistry, such as the formation of ureas, oximes and hydrazones; additions to carbon-carbon multiple bonds, especially oxidative addition, Michael additions of Nu-H reactants; and cycloaddition reactions, especially the Diels-Alder reaction (Lee et al., 2003; Lewis et al., 2002; Rostovtsev, 2002; Black et ai, 2008, Devaraj et al., 2008, Stockmann et al., 201 1 , Tornoe et al., 2002, Boren et ai, 2008, McNulty et al., 201 1 ; Himo et al., 2005; Moses et al., 2007; U.S. Patent No. 7,375,234; US Patent Publication NOs. 201 1/0077365 and 2010/0197871 ).

[0074] In one aspect of this embodiment, the reaction is carried out according to:

wherein B represents a pendant group that comprises a group suitable for participating in a click reaction with the cyclopropenium ion;

is selected from the group consisting of:

(42) (43) (44)

R-i-2 are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d.-ioalkoxy, C2-ioalkenyloxy, C2-ioalkynyloxy, d-ioalkyl, C3-iocycloalkyl, C2-ioalkenyl, C3-iocycloalkenyl, C2-ioalkynyl, halogen, aryloxy, heteroaryloxy, C2- ioalkoxycarbonyl, Ci-ioalkylthio, C2-ioalkenylthio, C2-ioalkynylthio, Ci-ioalkylsulfonyl, Ci-ioalkylsulfinyl, aryl-Ci-ioalkyl, heteroaryl-Ci-ioalkyl, aryl-Ci-ioheteroalkyl, heteroaryl-Ci-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein Ri and R2 are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R2 are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, C2-6alkenyl, C2-6alkynyl, aryl, C2- ₆ alkenyloxy, C2-6alkynyloxy, aryloxy, C2-6alkoxycarbonyl, Ci-6alkylthio, d- ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, d- ₆ alkylamino, Ci-6dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus; and C represents the linkage formed between the cyclopropenium ion and the polymer. Typically, the linkage, C, includes a covalent linkage.

[0075] Preferably, Ri and F¾ are independently selected from the group consisting of:

and combinations thereof.

[0076] Another embodiment of the present invention is a process for making a dendritic polymer. This process comprises the steps of: a. providing a first functionalized compound comprising a cyclopropenium ion, which has a reactive group at each position of the ring; and b. grafting a second functionalized compound onto each reactive group of the first functionalized compound such that chemical bonds are formed between the first functionalized compound and the second functionalized compound at the reactive groups, the second functionalized compound including reactive groups capable of forming bonds with the reactive groups on the cyclopropenium ion, and wherein the bonds are formed through a click chemistry mechanism.

[0077] The first and second compounds include any compound or polymer that will not prevent or substantially interfere in the click chemistry reaction. Selection of the particular first and second compounds is within the skill of the art and will be driven by the particular properties desired of the dendritic polymer. Non- limiting examples of the first and second compounds include the following:

[0078] As set forth above, the reactive groups on the respective first and second compounds are suitable for participation in click chemistry. Preferred reactive groups include without limitation azide, alkynyl, alkenyl, and thiol.

[0079] In one aspect of this embodiment, the first functionalized compound and the second functionalized compound are independently selected from a homopolymer or a copolymer, and are further independently selected from linear, branched, or dendritic polymers.

[0080] In another aspect of this embodiment, both the first and the second functionalized compounds comprise a cyclopropenium ion.

[0081] In yet another aspect of this embodiment, the first functionalized compound is:

[0082] In a further aspect of this embodiment, the second functionalized compound is selected from:

[0083] In yet another aspect of this embodiment, the reactive groups are located at a terminal position on the second functionalized compound.

[0084] In an additional aspect of this embodiment, a cycle defined by steps (a) and (b) is repeated at least once, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20 or more times, and the polymer formed at step (b) of the preceding cycle is a substrate for the providing step (a) in the subsequent cycle. Preferably, the cycle is repeated from 1 to 6 times.

[0085] An additional embodiment of the present invention is a stable, polycationic compound made by any process disclosed herein.

[0086] A further embodiment of the present invention is a polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH. The polymer has the structure:

wherein

X-i-2 are independently selected from the group consisting of CI, N, and any other atom suitable for participating in the process;

R-i-2 are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d-ioalkoxy, C2-ioalkenyloxy, C2-ioalkynyloxy, Ci-ioalkyl, C3-iocycloalkyl, C2-ioalkenyl, C3-iocycloalkenyl, C2-ioalkynyl, halogen, aryloxy, heteroaryloxy, C2- - _l oalkoxycarbonyl, Ci-ioalkylthio, C2-ioalkenylthio, C2-ioalkynylthio, Ci-ioalkylsulfonyl, d-ioalkylsulfinyl, aryl-Ci-ioalkyl, heteroaryl-Ci-ioalkyl, aryl-Ci-ioheteroalkyl, heteroaryl-d-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein Ri and R2 are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R2 are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, C2-6alkenyl, C2-6alkynyl, aryl, Ci-6alkoxy, C2- ₆ alkenyloxy, C2-6alkynyloxy, aryloxy, C2-6alkoxycarbonyl, Ci-6alkylthio, d- ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, d- ₆ alkylamino, Ci-6dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus; represents a suitable linking group; and

n is an integer.

[0087] In one aspect of this embodiment, the polymer is selected from the group consisting of a linear polymer, a branched polymer, a cross-linked polymer, and a dendritic polymer.

[0088] In another aspect of this embodiment, the polymer is a homopolymer or a heteropolymer. Suitable homopolymers and heteropolymers are as disclosed herein. Representative non-limiting examples of heteropolymers within the scope of the present invention include random copolymers, block copolymers, and graft copolymers.

[0089] In a further aspect of this embodiment, the polymer backbone is any suitable polymeric backbone having useful properties in accordance with the present invention. For example, the polymer backbone may be selected from the group consisting of ethylene, propylene, styrene, (meth)acrylate, vinyl chloride, urethane, ethylene terephthalate, ester, amide, norbornene, silicon, oxygen, and combinations thereof.

[0090] Preferred pH ranges are as disclosed above. [0091] In this embodiment of the present invention, the integer "n" is as previously defined.

[0092] A "suitable linking group" as used herein means a moiety that covalently connects a cyclopropenium ion to the polymer backbone, which moiety does not render the polymer unstable by, e.g., reaction with R-i or R ₂ groups. Suitable linking groups include, without limitation, no atom, unsubstituted and substituted functional groups such as amino, aryl, heteroaryl, alkoxy, alkenyloxy, alkynyloxy, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, ether, halogen, aryloxy, heteroaryloxy, alkoxycarbonyl, alkylthio, alkenylthio, alkynylthio, alkylsulfonyl, alkylsulfinyl, aryl- alkyl, heteroaryl-alkyl, aryl-heteroalkyl, heteroaryl-heteroalkyl, a phosphorus group, a silicon group and a boron group.

[0093] In another aspect of this embodiment, Ri _-2 are independently selected from the group consisting of

and combinations thereof.

[0094] In an additional aspect of this embodiment, the polymer is selected from the group consisting of:

(41)

(33) (37) (39)

[0095] Another embodiment of the present invention is a cross-linked polymer that comprises a stable cyclopropenium cation that remains positively charged at a high pH, the cross-linked polymer having the structure: polymer polymer polymer

(22a)

wherein ^%ii represents a suitable linking group; and

polymer is any polymer that can be bonded to the cyclopropenium ion.

[0096] In one aspect of this embodiment, the cross-linked polymer is selected from the group consisting of:

polymer

wherein polymer is any polymer that can be bonded to the cyclopropenium ion. Suitable polymers include, e.g., those whose backbones comprise ethylene, propylene, styrene, (meth)acrylate, vinyl chloride, urethane, ethylene terephthalate, ester, amide, norbornene, silicon, oxygen, or combinations thereof.

[0097] An additional embodiment of the present invention is a dendrimer having (1 ) a cationic core comprising a tri-functional cyclopropenium monomer and (2) at least two ordered dendritic core branches which (a) are covalently bonded to the cationic core, (b) extend through at least two generations, and (c) have at least 3 terminal groups per core branch.

[0098] In one aspect of this embodiment, the cationic core is:

[0099] In another aspect of this embodiment, the dendritic core branches are independently selected from:

[0100] Another embodiment of the present invention is a process for incorporating a cyclopropenium ion into a polymeric system. This process comprises contacting a functionalized cyclopropene with a functionalized compound capable of reacting with the functionalized cyclopropene for a period of time and under conditions suitable for the functionalized cyclopropene and the functionalized compound to react and form a polymeric system that comprises a stable cyclopropenium cation that remains positively charged at a high pH.

[0101] In one aspect of this embodiment, the functionalized cyclopropene is a compound of formula (200):

(200)

wherein

X-i-3 are independently selected from the group consisting of CI, N and any other atoms suitable for participating in the process; and

Ri _-4 are independently selected from the group consisting of no atom, amino, aryl, heteroaryl, d-ioalkoxy, C2-ioalkenyloxy, C2-ioalkynyloxy, d-ioalkyl, C3-iocycloalkyl, C2-ioalkenyl, C3-iocycloalkenyl, C2-ioalkynyl, halogen, aryloxy, heteroaryloxy, C2- - _l oalkoxycarbonyl, d-ioalkylthio, C2-ioalkenylthio, C2-ioalkynylthio, Ci-ioalkylsulfonyl, Ci-ioalkylsulfinyl, aryl-d-ioalkyl, heteroaryl-Ci-ioalkyl, aryl-Ci-ioheteroalkyl, heteroaryl-Ci-ioheteroalkyl, a phosphorus group, a silicon group and a boron group, wherein Ri and R2 or R ₃ and R ₄ are optionally combined to form a 5 to 8-membered carbocyclic or heterocyclic ring; further wherein the aliphatic or aromatic portions of Ri and R2 are optionally substituted with from 1 to 4 substituents selected from the group consisting of halogen, cyano, nitro, Ci _-4 alkyl, d-ealkenyl, d-ealkynyl, aryl, d- ₆ alkoxy, d-ealkenyloxy, d-ealkynyloxy, aryloxy, d-ealkoxycarbonyl, Ci-6alkylthio, d- ₆ alkylsulfonyl, Ci _-6 alkylsulfinyl, oxo, imino, thiono, primary amino, carboxyl, d- ₆ alkylamino, Ci-6dialkylamino, amido, nitrogen heterocycles, hydroxy, thiol and phosphorus. Preferably, the functionalized cyclopropene

(201 )

[0103] In another preferred embodiment, Xi _-2 are both N, and R-i-2 are independently selected from the group consisting of C _h alky!, aryl, and C3-iocycloalkyl. More preferably, R-i-2 are both cyclohexyl.

[0104] In another aspect of this embodiment, the functionalized compound capable of reacting with the functional group of the functionalized cyclopropene is a polymer selected from the group consisting of a linear polymer, a branch polymer, a cross-linked polymer, and a dendritic polymer.

[0105] Preferably, the polymer is a homopolymer or a heteropolymer. In one preferred embodiment, the polymer is a homopolymer of poly(N- alkylamino)methylstyrene.

[0106] In another preferred embodiment, the polymer is a heteropolymer, such as a random copolymer or a block polymer. More preferably, the random copolymer is a copolymer of polystyrene and poly(N-alkylamino)methylstyrene. Preferred block polymers include diblock copolymer, such as one that has the following structure:

wherein

x, y, and z are independently selected from integers greater than or equal to zero, and

R is any group that is suitable for participating in the process of incorporating the cyclopropenium ion into the polymeric system, x, y, and z may range from 0-1 ,000, including 0-500, 0-250, 0-100, 0-50, 0-25, 0-10, and 0-5. For example, x, y, and z may be independently selected from 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0107] A stable, polycationic compound made by the process disclosed herein may be self-assembling when contacted with a substrate. As used herein, "self- assembling" refers to a process in which molecules (including macromolecules such as polymers) form ordered structures, such as spheres, cylinders, lamellae, vesicles, as a consequence of interactions among the molecules themselves. Such ordered structures may be on the scale of nanometers, and thus, polymers, especially block polymers, are suitable for different applications in various fields, such as biomedicine, biomaterials, microelectronics, photoelectric materials, and catalysis. Self-assembly of polymers may further be directed by modifying confinement conditions, surface of the substrate in contact with the polymers (including graphoepitaxy and chemical registration techniques), and thermal and solvent annealing conditions. Such methods are known in the art and are disclosed in e.g.,, Albert et al., 2010; Mai et al., 2012; and Takenaka et al., 2013.

[0108] A further embodiment of the present invention is a substrate. This substrate comprises a stable, polycationic compound made by any process disclosed herein. A "substrate" as used in this embodiment may take any form convenient to the end use, such as, e.g., a film, a bead, a gel, a membrane, a coating, a powder, and the like. A non-limiting exemplary substrate made by the process disclosed herein is shown in Figure 3.

[0109] Another embodiment of the present invention is a support coated with any substrate disclosed herein for use in a water purification system.

[0110] The support generally serves as a mechanical structure for the coating substrate. The support may be made from the same polymer as the coating material or from one or more different polymers.

[0111] The support coated with one or more substrates disclosed herein may be used, inter alia, to adsorb contaminants, to disinfect (i.e., used as an antimicrobial), or for reverse osmosis {e.g., for desalination).

[0112] Methods of coating a support are known in the art and such methods may be used to coat a support with a substrate according to the present invention. Such methods include, without limitation, spin-coating, dip-coating, interfacial polymerization, painting, spraying, electrophoretic deposition, tape casting, and Langmuir-Blodget coating, phase inversion (polymer precipitation), such as those disclosed in e.g., U.S. Pat. Nos. 4,728,576; 5,069,156; and 5,844,192; U.S. Patent Publication No. 2006/0049540; Krogman et al., 2009; Kesting, 1985; Cabasso, 1987; Strathmann, 1990. Multiple layers may be deposited using layer-by layer methods, such as those disclosed in e.g., Decher et al., 1997. [0113] In currently available water purification systems, the purification membranes used typically lack tunable mechanical properties and can be brittle. Furthermore, the chemistry for making such membranes is difficult to manage due to the fact that typically, acid chlorides used to make the membrane must be processed in dry conditions because upon contact with water, acid chlorides reacts with water to form the corresponding carboxylic acids. See, e.g., Porter, 1990. The new substrates disclosed herein can be used with a wide variety of cross-linking units to tune the mechanical properties. Furthermore, the chemistry disclosed herein to make the water purification membrane can be done at a bench top, in the presence of water, under ambient conditions, and in as little as a few seconds. Furthermore, the chemistry disclosed herein is versatile and may be used to make antimicrobial coatings and substrates for cell cultures, as disclosed in more detail below.

[0114] The chemistry disclosed herein is also modular. For example, functionalized cyclopropenium cations may be linked to any preformed polymer with the corresponding functional group by click chemistry. Moreover, functionalized cyclopropenium cations may serve as dendritic cores, and various dendritic core branches may be added onto the cores. In addition, the cyclopropenium cation units can be obtained from readily available precursors and the chemistry is robust, efficient, and user-friendly. Furthermore, it provides a new level of functionality in materials science, yielding a cationic species that can maintain its charge at high pH.

[0115] Yet another embodiment of the present invention is an antimicrobial coating comprising any substrate disclosed herein. The term "antimicrobial," as used herein, means that the present coatings inhibit, prevent, or destroy the growth or proliferation of microorganisms, such as viruses, bacteria, and fungi. [0116] Polymers bearing quaternary ammonium cations have antibacterial activities. Furthermore, it has been shown that antibacterial activity increased with the increase of the amount of quaternary ammonium groups in the polymer (Kenawy et ai, 2007). Other groups that may be incorporated into the antibacterial coatings of the present invention include phosphonium and pyridinium groups. Therefore, it is expected that polymeric systems containing cyclopropenium cations as disclosed herein will have similar antibacterial activities. It is also expected that antibacterial activity will increase with the increase of the amount of cyclopropenium cations incorporated in the polymer.

[0117] In one aspect of this embodiment, a stable cationic dendritic polymer may be deposited onto electrospun sheets, beads coated on sutures, and on, e.g., dental restorative materials for local antibiotic therapy in various infections.

[0118] Preferably, the antimicrobial coating further comprises additional antimicrobial agents, such as silver or organic compounds, for example, sesquiterpenoids, penicillin, 2-benzimidazole carbamoyl. Preferably, silver in the form of nanoparticles are incorporated into the antimicrobial coating. More preferably, the silver nanoparticles are in the size range of 1 -100 nm. Methods of incorporating additional antimicrobial agents into the substrate are known in the art. For example, silver may be incorporated into the coating by radical-mediated dispersion polymerization using radical initiators, such as AIBN, as disclosed in Song et ai, 2012. Other methods of incorporating the organic antimicrobial agents into the substrate are reviewed in Kenawy et al., 2007.

[0119] An additional embodiment of the present invention is an ion-transport membrane comprising any substrate disclosed herein. Such a membrane would allow for the diffusion of ions and are useful in, e.g., dialysis, desalination, gas separations, batteries and fuel cells. Exemplary ion transport membrane assemblies for fuel cells or batteries include those disclosed in, e.g., U.S. Patent Nos. 6,565,632 and 7,335,247; and U.S. Patent Publication Nos. 2007/0137478, 201 1/0294653, and 201 1/0067405. Generally, fuel cells or batteries contain oxygen ion transport membranes, which conduct oxygen ions. Oxygen ion transport membranes have a cathode side, on which oxygen ionizes by gaining electrons. The substrates disclosed herein are useful in coating the anode side of the membrane, on which the oxygen ions lose electrons and reconstitute into elemental oxygen. Composite oxygen ion transport membranes are known in the art and are disclosed in e.g., U.S. Patent Nos. 7,556,676, 7,338,624, and 5,240,480; and U.S. Patent Publication Nos. 2005/0061663, and 2005/0013933. The substrates disclosed herein are useful for (electro)dialysis because the electrical potential difference on the two sides of the membrane allows the transport of charged species. Electrodialysis apparatus are known in the art and are disclosed in e.g., U.S. Patent Nos. 2,970,098, 5,643,430, 6,402,917, and 6,461 ,491 ; and U.S. Patent Publication No. 2005/0183956. One of the ways to desalinate water is use an electrodialysis process in which pairs of anionic and cationic membranes are placed such that salt water is separated into diluted solution and concentrated brine. Desalination systems are known in the art and are disclosed in e.g., U.S. Patent Nos. 4,539,088 and 4,539,091 ; and U.S. Patent Publication No. 201 1/0056876, 2010/0282689, and 2010/0314313.

[0120] Another embodiment of the present invention is a cell support comprising any substrate disclosed herein. Such a cell support may be used for culturing of cells, such as e.g., stem cells. Generally, cell cultures are maintained in plastic dishes, the surface of which are negatively charged. Thus, some anchorage- dependent cell types, such as stem cells, do not produce sufficient amounts of positively charged extracellular matrix proteins, adhering only weakly to the plastic substratum. Accordingly, cationic substrates according to the present invention may be used to provide support for such cells. Typically, the cationic substrates include a cyclopropenium ion according to the present invention as part of a polymeric system that also includes one or more cell culture compatible monomers such as, e.g., iminoethylene, methacrylate {e.g., choline methacrylate), and others known in the art such as those disclosed in Vendra et al., 2010.

[0121] Yet another embodiment of the present invention is a drug delivery vehicle comprising a stable cationic dendritic polymer made according to any method disclosed herein. The cationic dendrite polymer of the present invention is well- suited to carry negatively charged DNA into living cells.

[0122] Drug delivery vehicles containing guanidine have also been shown to be effective mimics of cell-penetrating peptides. The charged nature of a cationic dendritic polymer made according to the methods disclosed herein can also be used to mimic these types of materials, which may be useful in drug delivery. The high degree of branching of dendrimers also make them well-suited for drug delivery. For a review, see Gillies et al., 2005. Preferably, the core branches of the dendrimer are selected so that they are compatible with introduction into living organisms, e.g., they are non-toxic and on-immunogenic. See, e.g., Vendra et al., 2010. The drug delivery vehicles of the present invention may be used to deliver one or more agents into a living organism, such as, e.g., a cell or a mammal, including a human. Representative, non-limiting examples of drugs that may be delivered according to the present invention include adenosine deaminase, doxorubicin, interferon a-2b, and granulocyte colony stimulating factor. [0123] A further embodiment of the present invention is a gene therapeutic vector comprising a stable cationic dendritic polymer made according to any method disclosed herein. Exemplary, non-limiting examples of monomer units that may be incorporated into the dendritic polymer of the present invention include (poly)( - aminoesters), (poly)(2-aminoethylpropylenephosphate), allylamine, and the like. See, e.g., Vendra et al., 2010.

[0124] As used herein, a "gene therapeutic vector" means a vehicle used to transfer genetic material to a target cell. The gene therapeutic vector may be administered in vivo or in vitro. Preferably the cell is a mammalian cell, but other types of cells, e.g., insect, plant, or fungal, or non-mammalian vertebrate cells may be used.

[0125] In operation, the genetic material, which may be nucleic acids, such as DNA, RNA, RNAi, mRNA, tRNA, short hairpin RNA (shRNA), short interfering RNA (siRNA), double-stranded RNA (dsRNA), transcriptional gene silencing RNA (ptgsRNA), Piwi-interacting RNA, pri-miRNA, pre-miRNA, micro-RNA (miRNA), or anti-miRNA (as described, e.g., in U.S. Patent Application Nos. 1 1/429,720, 1 1/384,049, 1 1/418,870, and 1 1/429,720 and Published International Application Nos. WO 2005/1 16250 and WO 2006/126040), is reversibly linked to one or more of the dendrititc core branches. Upon delivery of the gene therapeutic vector to the target cell, the nucleic acid(s) are released.

Additional Definitions.

[0126] In the foregoing embodiments, the following definitions apply.

[0127] The term "alkoxy" refers to an alkyl group, preferably a lower alkyl group, having an oxygen attached thereto. Representative alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, tert-butoxy and the like. Other alkoxy groups within the scope of the present invention include, for example, the following:

[0128] The term "alkoxycarbonyl" refers to a carbonyl group substituted with an alkoxy group.

[0129] The term "alkenyl", as used herein, refers to an aliphatic group containing at least one double bond and is intended to include both "unsubstituted alkenyls" and "substituted alkenyls", the latter of which refers to alkenyl moieties having substituents replacing a hydrogen on one or more carbons of the alkenyl group. Such substituents may occur on one or more carbons that are included or not included in one or more double bonds. Moreover, such substituents include all those contemplated for alkyl groups, as discussed below, except where stability is prohibitive. For example, substitution of alkenyl groups by one or more alkyl, carbocyclyl, aryl, heterocyclyl, or heteroaryl groups is contemplated.

[0130] The term "alkene functionalized" compound means a compound containing a -C=C group.

[0131] The term "alkenyloxy" refers to an alkenyl group having an oxygen attached thereto. [0132] The term "alkenylthio", as used herein, refers to a thiol group substituted with an alkenyl group and may be represented by the general formula alkenyl-S-.

[0133] The term "alkyl" refers to the radical of saturated aliphatic groups, including straight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl (alicyclic) groups, alkyl-substituted cycloalkyl groups, and cycloalkyl-substituted alkyl groups. In certain embodiments, a straight chain or branched chain alkyl has 10 or fewer carbon atoms in its backbone (e.g., d-do for straight chains, C3-C10 for branched chains). Likewise, certain cycloalkyls have from 3-8 carbon atoms in their ring structure, including 5, 6 or 7 carbons in the ring structure.

[0134] Moreover, unless otherwise indicated, the term "alkyl" (or "lower alkyl") as used throughout the specification, examples, and claims is intended to include both "unsubstituted alkyls" and "substituted alkyls", the latter of which refers to alkyl moieties having substituents replacing a hydrogen on one or more carbons of the hydrocarbon backbone. Such substituents can include, for example, a halogen, a hydroxyl, a carbonyl (such as a carboxyl, an alkoxycarbonyl, a formyl, or an acyl), a thiocarbonyl (such as a thioester, a thioacetate, or a thioformate), an alkoxyl, a phosphoryl, a phosphate, a phosphonate, a phosphinate, an amino, an amido, an amidine, an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, a sulfate, a sulfonate, a sulfamoyl, a sulfonamido, a sulfonyl, a heterocyclyl, an aralkyl, an aromatic, or heteroaromatic moiety. It will be understood by those skilled in the art that the moieties substituted on the hydrocarbon chain can themselves be substituted, if appropriate. For instance, the substituents of a substituted alkyl may include substituted and unsubstituted forms of amino, azido, imino, amido, phosphoryl (including phosphonate and phosphinate), sulfonyl (including sulfate, sulfonamido, sulfamoyi and sulfonate), and silyl groups, as well as ethers, alkylthios, carbonyls (including ketones, aldehydes, carboxylates, and esters), -CF ₃ , -CN and the like. Exemplary substituted alkyls are described below. Cycloalkyls can be further substituted with alkyls, alkenyls, alkoxys, alkylthios, aminoalkyls, carbonyl- substituted alkyls, -CF3, -CN, and the like.

[0135] The term "Cx-y" when used in conjunction with a chemical moiety, such as, alkyl, alkenyl, or alkoxy is meant to include groups that contain from x to y carbons in the chain. For example, the term "C _x-y alkyl" refers to substituted or unsubstituted saturated hydrocarbon groups, including straight-chain alkyl and branched-chain alkyl groups that contain from x to y carbons in the chain, including haloalkyl groups such as trifluoromethyl and 2,2,2-tirfluoroethyl, etc. The terms "C2- _y alkenyl" and "C2 _-y alkynyl" refer to substituted or unsubstituted unsaturated aliphatic groups analogous in length and possible substitution to the alkyls described above, but that contain at least one double or triple bond respectively.

[0136] The term "alkylamino", as used herein, refers to an amino group substituted with at least one alkyl group.

[0137] The term "alkylsulfinyl" means a sulfinyl group substituted with an akyl group.

[0138] The term "alkylsulfonyl" means a sulfonyl group substituted with an akyl group.

[0139] The term "alkylthio", as used herein, refers to a thiol group substituted with an alkyl group and may be represented by the general formula alkylS-.

[0140] The term "alkynyl", as used herein, refers to an aliphatic group containing at least one triple bond and is intended to include both "unsubstituted alkynyls" and "substituted alkynyls", the latter of which refers to alkynyl moieties having substituents replacing a hydrogen on one or more carbons of the alkynyl group. Such substituents may occur on one or more carbons that are included or not included in one or more triple bonds. Moreover, such substituents include all those contemplated for alkyl groups, as discussed above, except where stability is prohibitive. For example, substitution of alkynyl groups by one or more alkyl, carbocyclyl, aryl, heterocyclyl, or heteroaryl groups is contemplated.

[0141] The term "alkynyloxy" means an alkynyl group having an oxygen attached thereto.

[0142] The term "alkynylthio", as used herein, refers to a thiol group substituted with an alkynyl group and may be represented by the general formula alknyl-S-.

[0143] The term "amide", as used herein in the context of polymers, refers to a backbone containing the functional group::

wherein R ⁷ represent a hydrogen or hydrocarbyl group.

[0144] The term "amido", as used herein, refers to a group

wherein R ⁷ and R ⁸ each independently represent a hydrogen or hydrocarbyl group, or R ⁷ and R ⁸ taken together with the N atom to which they are attached complete a heterocycle having from 4 to 8 atoms in the ring structure. [0145] The terms "amine" and "amino" are art-recognized and refer to both unsubstituted and substituted amines and salts thereof, e.g., a moiety that can be represented by

wherein R ⁷ , R ⁸ , and R ⁸ each independently represent a hydrogen or a hydrocarbyl group, or R ⁷ and R ⁸ taken together with the N atom to which they are attached complete a heterocycle having from 4 to 8 atoms in the ring structure. The term "primary" amine means only one of R ⁷ and R ⁸ or one of R ⁷ , R ⁸ , and R ⁸ is a hydrocarbyl group. Secondary amines have two hydrocarbyl groups bound to N. In tertiary amines, all three groups, R ⁷ , R ⁸ , and R ⁸ , are replaced by hydrocarbyl groups.

[0146] The term "aryl" as used herein includes substituted or unsubstituted single-ring aromatic groups in which each atom of the ring is carbon. Preferably the ring is a 3- to 8-membered ring, more preferably a 6-membered ring. The term "aryl" also includes polycyclic ring systems having two or more cyclic rings in which two or more carbons are common to two adjoining rings wherein at least one of the rings is aromatic, e.g., the other cyclic rings can be cycloalkyls, cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls. Aryl groups include benzene, naphthalene, phenanthrene, phenol, aniline, and the like.

[0147] As used herein, "aryloxy" means which an aryl group singularly bonded to oxygen.

[0148] The term "aryl-alkyl" means an alkyl group substituted with aryl.

[0149] The term "aryl-heteroalkyl" means an heteroalkyl group substituted with aryl.

[0150] The term "azide" means a functional group containing -N ₃ . [0151] The terms "carbocycle", "carbocyclyl", and "carbocyclic", as used herein, refer to a non-aromatic saturated or unsaturated ring in which each atom of the ring is carbon. Preferably a carbocycle ring contains from 3 to 8 atoms, including 5 to 7 atoms, such as for example, 6 atoms.

[0152] The term "carbonyl" means a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. Carbonyls include without limitation, aldehydes, ketones, carboxylic acids, esters, and amides.

[0153] The terms "carboxy" and "carboxyl", as used herein, refer to a group represented by the formula -CO ₂ H.

[0154] The term "carboxylate" refers to the conjugate base of a carboxyl group, represented by the formula -COO ^" .

[0155] The term "cyano" means of a functional group composed of a carbon atom triple-bonded to a nitrogen atom: -C≡N.

[0156] The term "cycloalkyl" means a univalent groups derived from cycloalkanes by removal of a hydrogen atom from a ring carbon atom.

[0157] The term "cycloalkenyl" means a univalent groups derived from cycloalkenes by removal of a hydrogen atom from a ring carbon atom.

[0158] The term "ester", as used herein in the context of polymers, refers to a backbone containing the functional group:

[0159] The term "ether", as used herein, refers to a hydrocarbyl group linked through an oxygen to another hydrocarbyl group. Accordingly, an ether substituent of a hydrocarbyl group may be hydrocarbyl-O-. Ethers may be either symmetrical or unsymmetrical. Examples of ethers include, but are not limited to, heterocycle-O- heterocycle and aryl-O-heterocycle. Ethers include "alkoxyalkyl" groups, which may be represented by the general formula alkyl-O-alkyl.

[0160] The term "ethylene" as used herein in the context of polymers, refers to a backbone containing the functional group:

[0161] The term "ethylene terephthalate refers to the following functional group:

[0162] The terms "halo" and "halogen" are used interchangeably herein and mean halogen and include chloro, fluoro, bromo, and iodo.

[0163] The term "heteroaryl" includes substituted or unsubstituted aromatic single ring structures, preferably 3- to 8-membered rings, more preferably 5- to 7- membered rings, even more preferably 5- to 6-membered rings, whose ring structures include at least one heteroatom, preferably one to four heteroatoms, more preferably one or two heteroatoms. The term "heteroaryl" also includes polycyclic ring systems having two or more cyclic rings in which two or more carbons are common to two adjoining rings wherein at least one of the rings is heteroaromatic, e.g., the other cyclic rings can be cycloalkyls, cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls. Heteroaryl groups include, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrazine, pyridazine, and pyrimidine, and the like.

[0164] As used herein, "heteroaryloxy" means which a heteroaryl group singularly bonded to oxygen.

[0165] "Heteroaryl-alkyl" means a alkyl group substituted with a heteroaryl group.

[0166] "Heteroaryl-heteroalkyl" means a heteroalkyl group substituted with a heteroaryl group.

[0167] The term "heteroatom" as used herein means an atom of any element other than carbon or hydrogen. Preferred heteroatoms are nitrogen, oxygen, and sulfur.

[0168] The term "heteroalkyl" means an alkyl in which at least one carbon of a hydrocarbon backbone is substituted with a heteroatom. Heteroalkyls include alkoxyalkyls, such as d-s alkoxyalkyl.

[0169] The term "heteroaromatic" means at least one carbon atoms in the aromatic group is substituted with a heteroatom.

[0170] The terms "heterocyclyl", "heterocycle", "heterocyclic", and the like refer to substituted or unsubstituted non-aromatic ring structures, preferably 3- to 8- membered rings, whose ring structures include at least one heteroatom, preferably one to four heteroatoms, more preferably one or two heteroatoms. For example, "nitrogen heterocycle" means to substituted or unsubstituted non-aromatic ring structures, whose ring structures contain at least one nitrogen. The terms "heterocyclyl," "heterocyclic," and the like also include polycyclic ring systems having two or more cyclic rings in which two or more carbons are common to two adjoining rings wherein at least one of the rings is heterocyclic, e.g., the other cyclic rings can be cycloalkyls, cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls. Heterocyclyl groups include, for example, piperidine, piperazine, pyrrolidine, morpholine, lactones, lactams, and the like.

[0171] The term "hydrocarbyl", as used herein, refers to a group that is bonded through a carbon atom that does not have a =O or =S substituent, and typically has at least one carbon-hydrogen bond and a primarily carbon backbone, but may optionally include heteroatoms. Thus, groups like methyl, ethoxyethyl, 2- pyridyl, and trifluoromethyl are considered to be hydrocarbyl for the purposes of this application, but substituents such as acetyl (which has a =O substituent on the linking carbon) and ethoxy (which is linked through oxygen, not carbon) are not. Hydrocarbyl groups include, but are not limited to aryl, heteroaryl, carbocycle, heterocycle, alkyl, alkenyl, alkynyl, and combinations thereof.

[0172] The term "hydroxyalkyl", as used herein, refers to an alkyl group substituted with a hydroxy group.

[0173] The term "hydroxyl" or "hydroxy," as used herein, refers to the group - OH.

[0174] The term "imino" group means a functional group containing a carbon- nitrogen double bond.

[0175] The term "lower" when used in conjunction with a chemical moiety, such as, acyl, alkyl, alkenyl, alkynyl, or alkoxy is meant to include groups where there are ten or fewer non-hydrogen atoms in the substituent, preferably eight or fewer, such as for example, from about 2 to 8 carbon atoms, including less than 6 carbon atoms. A "lower alkyl", for example, refers to an alkyl group that contains ten or fewer carbon atoms, preferably eight or fewer. In certain embodiments, acyl, alkyl, alkenyl, alkynyl, or alkoxy substituents defined herein are respectively lower acyl, lower alkyl, lower alkenyl, lower alkynyl, or lower alkoxy, whether they appear alone or in combination with other substituents, such as in the recitations hydroxyalkyi and aralkyi (in which case, for example, the atoms within the aryl group are not counted when counting the carbon atoms in the alkyl substituent).

[0176] The term "(meth)acrylate" refers to the following functional group:

[0177] The term "nitro" means the functional group -NO ₂ .

[0178] The term "norbornene" refers to the following functional group:

[0179] The terms "polycyclyl", "polycycle", and "polycyclic" refer to two or more rings (e.g., cycloalkyls, cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls) in which two or more atoms are common to two adjoining rings, e.g., the rings are "fused rings". Each of the rings of the polycycle can be substituted or unsubstituted. In certain embodiments, each ring of the polycycle contains from 3 to 10 atoms in the ring, preferably from 3 to 8, such as for example, 5 to 7.

[0180] The term "propylene" refers to the following functional group:

[0181] The term "oxo" refers to the group =O.

[0182] The term "substituted" refers to moieties having substituents replacing a hydrogen on one or more carbons of the backbone. It will be understood that "substitution" or "substituted with" includes the implicit proviso that such substitution is in accordance with the permitted valence of the substituted atom and the substituent, and that the substitution results in a stable compound, e.g., which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. As used herein, the term "substituted" is contemplated to include all permissible substituents of organic compounds. In a broad aspect, the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and non-aromatic substituents of organic compounds. The permissible substituents can be one or more and the same or different for appropriate organic compounds. For purposes of this invention, the heteroatoms such as nitrogen may have hydrogen substituents and/or any permissible substituents of organic compounds described herein which satisfy the valences of the heteroatoms. Substituents can include any substituents described herein, for example, a halogen, a hydroxyl, a carbonyl (such as a carboxyl, an alkoxycarbonyl, a formyl, or an acyl), a thiocarbonyl (such as a thioester, a thioacetate, or a thioformate), an alkoxyl, a phosphoryl, a phosphate, a phosphonate, a phosphinate, an amino, an amido, an amidine, an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, a sulfate, a sulfonate, a sulfamoyl, a sulfonamido, a sulfonyl, a heterocyclyl, an aralkyl, or an aromatic or heteroaromatic moiety. It will be understood by those skilled in the art that the moieties substituted on the hydrocarbon chain can themselves be substituted, if appropriate.

[0183] The term "styrene" refers to the following functional group:

[0184] As used herein, the term "substituent," means H, cyano, oxo, nitro, acyl, acylamino, halogen, hydroxy, amino acid, amine, amide, carbamate, ester, ether, carboxylic acid, thio, thioalkyl, thioester, thioether, d-e alkyl, d-salkoxy, d- ₈ alkenyl, d-earalkyl, 3- to 8-membered carbocyclic, 3- to 8-membered heterocyclic, 3- to 8-membered aryl, or 3- to 8-membered heteroaryl, sulfate, sulfonamide, sulfoxide, sulfonate, sulfone, alkylsulfonyl, and arylsulfonyl.

[0185] Unless specifically stated as "unsubstituted," references to chemical moieties herein are understood to include substituted variants. For example, reference to an "aryl" group or moiety implicitly includes both substituted and unsubstituted variants.

[0186] The term "sulfate" is art-recognized and refers to the group -OSO ₃ H, or a pharmaceutically acceptable salt thereof.

[0187] The term "sulfinyl" is art-recognized and refers to the group -S(O)-R ⁷ , wherein R ⁷ represents a hydrocarbyl.

[0188] The term "sulfonyl" is refers to the group -S(O) ₂ -R ⁷ , wherein R ⁷ represents a hydrocarbyl.

[0189] The term "thio" or "thiol", as used herein, refers to the -SH group. [0190] The term "thioalkyl", as used herein, refers to an alkyl group substituted with a thiol group.

[0191] The term "thiono" refers to a substitution on a carbon atom, more specifically to a doubly bonded sulfur.

[0192] The term "urethane" refers to the following functional group:

wherein R and R' are independently selected from aryls or alkyls.

[0193] The term "vinyl chloride" refers to the following functional group:

[0194] It is understood that the disclosure of a compound herein encompasses all stereoisomers of that compound. As used herein, the term "stereoisomer" refers to a compound made up of the same atoms bonded by the same bonds but having different three-dimensional structures which are not interchangeable. The three-dimensional structures are called configurations. Stereoisomers include enantiomers, optical isomers, and diastereomers.

[0195] The terms "racemate" or "racemic mixture" refer to a mixture of equal parts of enantiomers. The term "chiral center" refers to a carbon atom to which four different groups are attached. The term "enantiomeric enrichment" as used herein refers to the increase in the amount of one enantiomer as compared to the other. [0196] It is appreciated that compounds of the present invention having a chiral center may exist in and be isolated in optically active and racemic forms. Some compounds may exhibit polymorphism. It is to be understood that the present invention encompasses any racemic, optically-active, diastereomeric, polymorphic, or stereoisomeric form, or mixtures thereof, of a compound of the invention, which possess the useful properties described herein, it being well known in the art how to prepare optically active forms (for example, by resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by chiral synthesis, or by chromatographic separation using a chiral stationary phase).

[0197] Examples of methods to obtain optically active materials are known in the art, and include at least the following:

i) physical separation of crystals~a technique whereby macroscopic crystals of the individual enantiomers are manually separated. This technique can be used if crystals of the separate enantiomers exist, i.e., the material is a conglomerate, and the crystals are visually distinct;

ii) simultaneous crystallization-a technique whereby the individual enantiomers are separately crystallized from a solution of the racemate, possible only if the latter is a conglomerate in the solid state; iii) enzymatic resolutions-a technique whereby partial or complete separation of a racemate by virtue of differing rates of reaction for the enantiomers with an enzyme;

iv) enzymatic asymmetric synthesis~a synthetic technique whereby at least one step of the synthesis uses an enzymatic reaction to obtain an enantiomerically pure or enriched synthetic precursor of the desired enantiomer;

v) chemical asymmetric synthesis-a synthetic technique whereby the desired enantiomer is synthesized from an achiral precursor under conditions that produce asymmetry (i.e., chirality) in the product, which may be achieved using chiral catalysts as disclosed in more detail herein or chiral auxiliaries;

vi) diastereomer separations~a technique whereby a racemic compound is reacted with an enantiomerically pure reagent (the chiral auxiliary) that converts the individual enantiomers to diastereomers. The resulting diastereomers are then separated by chromatography or crystallization by virtue of their now more distinct structural differences and the chiral auxiliary later removed to obtain the desired enantiomer; vii) first- and second-order asymmetric transformations-a technique whereby diastereomers from the racemate equilibrate to yield a preponderance in solution of the diastereomer from the desired enantiomer or where preferential crystallization of the diastereomer from the desired enantiomer perturbs the equilibrium such that eventually in principle all the material is converted to the crystalline diastereomer from the desired enantiomer. The desired enantiomer is then released from the diastereomer;

viii) kinetic resolutions-this technique refers to the achievement of partial or complete resolution of a racemate (or of a further resolution of a partially resolved compound) by virtue of unequal reaction rates of the enantiomers with a chiral, non-racemic reagent or catalyst under kinetic conditions;

ix) enantiospecific synthesis from non-racemic precursors~a synthetic technique whereby the desired enantiomer is obtained from non-chiral starting materials and where the stereochemical integrity is not or is only minimally compromised over the course of the synthesis;

x) chiral liquid chromatography-a technique whereby the enantiomers of a racemate are separated in a liquid mobile phase by virtue of their differing interactions with a stationary phase. The stationary phase can be made of chiral material or the mobile phase can contain an additional chiral material to provoke the differing interactions;

xi) chiral gas chromatography~a technique whereby the racemate is volatilized and enantiomers are separated by virtue of their differing interactions in the gaseous mobile phase with a column containing a fixed non-racemic chiral adsorbent phase;

xii) extraction with chiral solvents~a technique whereby the enantiomers are separated by virtue of preferential dissolution of one enantiomer into a particular chiral solvent;

xiii) transport across chiral membranes-a technique whereby a racemate is placed in contact with a thin membrane barrier. The barrier typically separates two miscible fluids, one containing the racemate, and a driving force such as concentration or pressure differential causes preferential transport across the membrane barrier. Separation occurs as a result of the non-racemic chiral nature of the membrane which allows only one enantiomer of the racemate to pass through. [0198] The stereoisomers may also be separated by usual techniques known to those skilled in the art including fractional crystallization of the bases or their salts or chromatographic techniques such as LC or flash chromatography. The (+) enantiomer can be separated from the (-) enantiomer using techniques and procedures well known in the art, such as that described by J. Jacques, et ai, antiomers, Racemates, and Resolutions", John Wiley and Sons, Inc., 1981 . For example, chiral chromatography with a suitable organic solvent, such as ethanol/acetonitrile and Chiralpak AD packing, 20 micron can also be utilized to effect separation of the enantiomers.

[0199] The following examples are provided to further illustrate the compounds, compositions, and processes of the present invention. These examples are illustrative only and are not intended to limit the scope of the invention in any way.

EXAMPLES Example 1 Synthesis of Cyclopropenium Ions

Diaminochlorocvclopropenium ions (Formula 4)

[0200] A diaminochlorocyclopropenium ion (a compound within the scope of Formula 4, where Ri and R2 are H) may be synthesized according to equation (1 ) or equation (2), depending on the size of the R1R2 groups being added to tetrachlorocyclopropene (Compound 1 ). Bulkier groups (such as branched groups) tend to add twice, as in equation 1 , whereas smaller groups (such as linear or straight chain groups) tend to add three times, as in equation 2. See also Yoshida, 1973. In the Examples, unless specifically defined otherwise, the R groups are as defined previously in this application.

[0201] In general, an excess secondary amine of the formula HNR1R2 (Formula 2) is added to tetrachlorocyclopropene (compound 1 ) in methylene chloride. Formula 3 or Formula 4 is obtained after removal of the solvent. In general, removal of solvent is all that is required. If desired, column chromotagraphy may be used after any step. The identity and purity of the compound may be confirmed by H-NMR, C-NMR and low-resolution mass spectrometery.

[0202] If the reaction proceeds according to equation (2), water soluble Formula 3 may be converted to Formula 4 by the addition of potassium hydroxide in water followed by reaction with oxalyl chloride. If Formula 3 is not soluble in water, then a water/methanol mixture is used, and the reaction mixture is heated to 60°C- 80°C to solubilize Formula 3. The reaction with oxalyl chloride is done in dichloromethane solvent at room temperature.

[0203] A compound within the scope of Formula 4 in which Ri=R ₂ =cyclohexyl was synthesized as follows. To a solution of tetrachlorocyclopropene 1 , an excess amount of dicylohexylamine (Sigma Aldrich, St. Louis, MO) was added. The reaction mixture was stirred overnight at room temperature, followed by filtration and a 1 M HCI washing.

[0204] A compound within the scope of Formula 4 in which Ri=R ₂ =isopropyl was made similarly to the cyclohexyl variant, with the exception that the work-up consists of only removal of the solvent. This process yields Formula 4 (where Ri=R2=isopropyl) and a diisopropylamine hydrochloride salt in a 1 :1 mixture. The diisopropylamine was purchased from Sigma Aldrich.

[0205] A compound within the scope of Formula 3 where or Ri=R2=-(CH ₂ ) ₄ - were prepared following Breslow's protocol (Wilcox and Breslow, 1980). Conversion (step 2) was performed in dichloromethane by addition of oxalyl chloride to cyclopropenone intermediate. Unless otherwise noted, all starting materials in the Examples were purchased from Sigma Aldrich.

Cvclopropenium ions (Formula 6)

(4) (6)

[0206] A diaminochlorocyclopropenium ion (a compound within the scope of Formula 4) is reacted with an excess of a secondary amine of the formula HNR ₃ R (Formula 5) in methylene chloride. A compound within the scope of Formula 6 is obtained after removal of the solvent. If necessary, a water or 1 M HCI washing may be used to remove excess amine before removal of solvent. Example 2

Synthesis of Cross-Linked Polymer 22

Synthesis of compound 21

[0207] Tetrachlorocyclopropene (Compound 1 ) was reacted with excess diallylamine (Sigma Aldrich, catalog No. D9603, St. Louis, MO) in methylene chloride. After a water/1 M HCI washing and the removal of solvent, the cyclopropenium compound 21 was obtained.

[0208] Cross-linked Polymer 22 was generated using the thiol-ene chemistry described in Campos et al., 2008a.

[0209] In particular, poly[(mercaptopropyl)methylsiloxane] (PMMS) (molecular weight of approximately 4000-7000 g/mol) (which is within the scope of polymer 20) was reacted with cyclopropenium ion 21 in the presence of less than 0.1 wt % 2,2- dimethoxy-2-phenylacetophenone (DMPA) as the initiator. Curing with ultraviolet (UV) light resulted in the cross-linked polymer 22. Different ratios of PMMS to cyclopropenium ion 21 may be used. Ratios of 1 :1 , 1 :2, and 2:1 by mass were used. The resultant polymers are stiffer when a higher mass percentage of cyclopropenium ion 21 was used. All of the polymers, however, are flexible enough to be distorted by hand. An image of the cross-linked polymer is shown in Figure 3.

Thermally initiated reactions

[0210] Alternatively, the reaction is initiated thermally, using any thermal radical initiator to form polymer 22. For example, azobisisobutyronitrile (AIBN) is a radical initiator that can be blended in the system (for example, 3-10 wt %) and the polymerization can take place at temperatures higher than 70°C. If a different initiator is used with either a higher or lower decomposition temperature, then the cross- linking temperature can be varied as desired. Cross-linking time can also be varied from 5 minutes to several hours, depending on the temperature and radical initiator of choice.

Example 3

Synthesis of Other Cross-Linked Polymers

[0211] Many other cross-linked polymers may be obtained by reacting, e.g., any of the thiol compounds with any of the ene compounds listed below. The initiator for the reaction(s) may be, e.g., either AIBN as the thermo initiator or DMPA. Thiols

Synthesis of compound 25

[0212] Tetrachlorocyclopropene (Compound 1 ) was reacted with excess N- allylmethylamine (Sigma Aldrich, catalog No. 317748) in methylene chloride. After a water/1 M HCI wash and the removal of solvent, cyclopropenium compound 25 was obtained.

Synthesis of compound 23

(23)

[0213] The double bonds in compound 21 are reacted with thioacetic acid to form the corresponding thioester, which is then hydrolyzed under acetic conditions to form compound 23. Synthesis of compound 24

[0214] The double bonds in compound 25 are reacted with thioacetic acid to form the corresponding thioester, which is then hydrolyzed under acetic conditions to form compound 24.

Example 4

Synthesis of Linear Polymer Using "Grafting Though" Method

[0215] Linear polymers are made by the grafting through method using functional groups on the cydopropenium group to form the polymer backbones {e.g., polymers based on styrene, (meth)acrylates, norbonenes). Random copolymers and block copolymers are also made.

Polymers with polystyrene backbones, polymer 33

[0216] A compound within the scope of Formula 4 is reacted with excess 1 - piperazineethanol (compound 30) (Sigma Aldrich catalog number H28807) in methylene chloride to form compound 31. In this example, Ri and R ₂ may be the same or different and are independently selected from, e.g., the groups listed above.

polymer (33)

[0217] A compound within the scope of Formula 32 is made by treatment of a compound within the scope of Formula 31 with sodium hydride, followed by addition of 4-vinylbenzylchloride in DMF or THF. The resulting product, a compound within the scope of Formula 32, is purified by column chromatography.

[0218] A polymer within the scope of Formula 33 may be formed in accordance with Campos et al., 2008b. Briefly, a catalytic amount of AIBN is added to a compound within the scope of Formula 32 with a reversible addition-

fragmentation chain transfer (RAFT) agent, _j and heated. The contents are diluted with CH ₂ CI ₂ before precipitating into cold MeOH. The resulting polymer is dried in vacuo. Polymers with polystyrene backbones, Formula 37

(4)

(35)

[0219] A compound within the scope of Formula 4 is reacted with excess 2- (Methylamino)ethanol (compound 34) (Sigma Aldrich catalog number 471445) in methylene chloride to form a compound within the scope of Formula 35. In this example, Ri and R ₂ may be the same or different and are independently selected from, e.g., the groups listed above.

[0220] A compound within the scope of Formula 36 is made by treating a compound within the scope of Formula 35 with sodium hydride, followed by addition of 4-vinylbenzylchloride in DMF or THF. The resulting product, which is within the scope of Formula 36, is purified by column chromatography.

[0221] A polymer within the scope of Formula 37 may be formed in accordance with Campos et al., 2008b. Briefly, a catalytic amount of AIBN is added to a compound within the scope of Formula 36 in combination with a reversible

addition-fragmentation chain transfer (RAFT) agent,

heated. The contents are diluted with CH2CI2 before precipitating into cold MeOH. The resulting polymer, which is within the scope of Formula 37, is dried in vacuo. Depending on the solubility, the polymer may be precipitated into hexanes or a water/MeOH mixture. Precipitation tests can be performed on a small scale before scaling up. Polymers with polvmethacrylate backbones, Formula 39

polymer (39)

[0222] A compound within the scope of Formula 31 is dissolved in dichloromethane, cooled to 0°C, then triethylamine and methacryloyl chloride are added in excess. The reaction is then allowed to proceed overnight; followed by a water washing and column chromatography. The resulting product is a compound within the scope of Formula 38.

[0223] A polymer within the scope of Formula 39 may be formed in accordance with Campos et ai, 2008b. Briefly, a compound within the scope of Formula 38, ethyl-2-bromo isobutyrate, and N,N,N',N",N"- pentamethyldiethylenetriamine (PMDETA) are added to a flask and sparged with nitrogen. Copper(l) bromide is placed in a Schlenk flask with a stir bar and evacuated. The reagent mixture is heated to 75°C, with stirring. The solution is then diluted with CH ₂ CI ₂ and passed through neutral alumina to remove the excess copper. The solution is concentrated, and a polymer within the scope of Formula 39 is precipitated into hexanes and dried under vacuo as a final step. Additionally, precipitation may take place into methanol instead of hexanes, depending on the solubility of the polymer.

Polymers with polvmethacrylate backbones, Formula 41

(40)

[0224] A compound within the scope of Formula 35 is dissolved in dichloromethane, and the mixture is cooled to 0°C. Then triethylamine and methacryloyl chloride (Sigma Aldrich) are added in excess. The reaction is then allowed to proceed overnight. A water washing and column chromatography yield a compound within the scope of Formula 40.

[0225] A polymer within the scope of Formula 41 may be formed in accordance with Campos et ai, 2008b. Briefly, a compound within the scope of Formula 40, ethyl-2-bromo isobutyrate, and N,N,N',N",N"- pentamethyldiethylenetriamine (PMDETA) are added to a flask and sparged with nitrogen. Copper(l) bromide is placed in a Schlenk flask with a stir bar and evacuated. The reagent mixture is heated to 75°C, with stirring. The solution is then diluted with CH2CI2 and passed through neutral alumina to remove the excess copper. The solution is concentrated, and the a polymer within the scope of Formula 41 is precipitated into hexanes. Example 5

Synthesis of Linear Polymer Using "Grafting To" Method

[0226] The cyclopropenium group may also be grafted onto a pre-formed polymer using, e.g., click chemistry reactions, such as thiol-ene and azide/alkyne click reactions, as illustrated in Figure 1 . Suitable compounds for such click chemistry reactions include those shown below:

[0227] For example, a compound within the scope of Formula 42 is used in a reaction of a primary amine with an NHS-activated ester to make a corresponding amide. Compounds within the scope of Formulas 43 and 44 are used, e.g., in azide/alkyne click reactions, and a compound within the scope of Formula 45 is used in thiol-ene reactions, in accordance with the procedure disclosed in Campos et al., 2008b. [0228] Each of the starting compounds within the scope of Formulas 42-45 is made according to the synthesis scheme of equation 1 or 2, followed by equation 3.

[0229] As an alternative, a compound within the scope of Formula 45 may be formed according to the following synthesis scheme:

(46) (45)

[0230] A compound within the scope of Formula 4 is reacted with excess N- allylmethylamine (Sigma Aldrich, catalog No. 317748) in methylene chloride. A cyclopropenium compound within the scope of Formula 46 is obtained after removal of solvent. The double bond in a compound within the scope of Formula 46 is reacted with thioacetic acid to form the corresponding thioester, which is then hydrolyzed under acidic conditions to form a compound within the scope of Formula 45.

Example 6

Synthesis of Cyclopropenium Dendrimers

[0231] Dendrimers are synthesized using trifunctional monomers as shown in Figure 2. Many different strategies may be used to generate dentrimers with a core cyclopropenium cation.

[0232] For example, an accelerated AB ₂ /CD ₂ approach using both copper catalyzed azide alkyne cycloaddition (CuAAC) and a thiol-ene coupling reaction may be used to generate dendrimers, as disclosed in Antoni et al., 2010. Specifically, the following representative compounds are used for the strategy.

[0233] Compounds 46 and 47 will be used in one dendrimer synthesis, and compounds 46 and 48 will be used in another. The synthesis of compound 47 is disclosed in Antoni et al., 2010.

Synthesis of compound 46

[0234] Compound 25 is converted to compound 49 by the addition of potassium hydroxide in water followed by reaction with oxalyl chloride. Compound 49 is then reacted with excess methyl propargyl amine to yield compound 46.

Synthesis of compound 48

[0235] Tetrachlorocyclopropene (Compound 1 ) is reacted with excess 2- (methylamino)ethanol (compound 34) (Sigma Aldrich catalog number 471445) in accordance with equations 1 or 2 above to form compound 50.

(50)

[0236] Compound 50 is then reacted with excess N-allylmethylamine (Sigma Aldrich, catalog No. 317748) in methylene chloride. The double bonds in the resulting product are reacted with thioacetic acid to form the corresponding thioester, which is then hydrolyzed under acetic conditions to form the thiol group in compound 48. Esterification with the azide functional monomer yields compound 48.

First Generation Dendrimer: thiol-ene reaction

[0237] A first generation dendrimer may be obtained via a thiol-ene reaction between compounds 46 and 47 or compounds 46 and 48. The reaction is conducted in the presence of tris(allyloxy)triazine (TAT), as well as the radical initiator, 2,2- dimethoxy-2-phenylacetophenone (DMPA). The reaction solution is sparged with argon prior to irradiation with 365 nm UV light followed by simple filtration through a plug of silica to remove excess compound 47 or 48.

Second Generation Dendrimer: CuAAC reaction

[0238] Purified first generation dendrimer is then reacted with 1 .1 equivalents of 47 or 48 in THF/H ₂ O with CuSO ₄ and sodium ascorbate (NaAsc). The CuSO /NaAsc system (Rostovtsev et ai, 2002) is chosen because of its proven robust nature and monitoring of the CuAAC reaction using ¹ H NMR and FT-IR spectroscopy revealed full conversion of the peripheral azides. Concomitant with the loss of the CH ₂ N ₃ resonance at 3.3 ppm, new peaks in the region of 5.1 -5.9 ppm corresponding to the terminal alkenes of the fully converted second generation dendrimer may be observed in the ¹ H NMR spectrum. Additionally, FT-IR will be able to show complete disappearance of the azide stretch at 2091 cm ^-1 and reappearance of the terminal alkene vibrational transition at 923 cm ^-1 , thus confirming the quantitative nature of the second generation growth step.

Higher Generation Dendrimers

[0239] Higher generation dendrimers may be formed by performing additional cycles of the thiol/ene reaction (by utilizing, e.g., the process for making of the first generation dendrimer) and the CuAAC reaction (by utilizing, e.g., the process for making of the second generation dendrimer). Optionally, additional purification steps, for example, by filtration through a silica plug, simple precipitation, or a combination of extraction and precipitation, may be performed.

Example 7

Alternative Methods of Synthesizing Cyclopropenium-Containing Polymers

[0240] A further novel route according to the present invention to synthesize cyclopropenium containing polymers has been developed. In this method, a random copolymer of styrene and chloromethylstyrene (or a homopolymer of chloromethylstyrene) is reacted with either methylamine or isopropylamine to introduce an amine functional handle into the polymer. The resulting amine functionalized polymer is then reacted with dichlorocyclopropene in a substitution reaction to yield a tris(dialkylamino)cyclopropenium containing polymer. The reaction scheme for converting polymers containing polychloromethylstyrene to poly(N-alkylamino)methylstyrene, followed by substitution of the dichlorocyclopropene is as follows:

In the scheme above, x and y are independently selected from integers greater than or equal to zero, such as from 0-1 ,000, including 0-500, 0-250, 0-100, 0-50, 0-25, 0- 10, and 0-5.

[0241] Furthermore, this methodology may be applied to diblock copolymers to create cyclopropenium containing diblocks for the first time. The following scheme shows how diblock copolymers may be made using this method:

Diblock copolymer

In the scheme above, x, y, and z are independently selected from integers greater than or equal to zero, such as from 0-1 ,000, including 0-500, 0-250, 0-100, 0-50, 0- 25, 0-10, and 0-5. For example, x, y, and z may be independently selected from 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, and 10. R is any group that suitable for participating in the process, including substituted or unsubstituted alkyl, such as d-6 alkyl, preferably methyl or isopropyl groups.

[0242] Diblock copolymers can self-assemble into nanoscale patterns, and thus, nanopatterned cyclopropenium-containing surfaces may be made.

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[0243] All documents cited in this application are hereby incorporated by reference as if recited in full herein.

[0244] Although illustrative embodiments of the present invention have been described herein, it should be understood that the invention is not limited to those described, and that various other changes or modifications may be made by one skilled in the art without departing from the scope or spirit of the invention.