BACKGROUND Scientists have formed numerous different perhydroxylated molecules. Carbon- based systems are well-known. For example, carbohydrates are ubiquitous in nature and serve as a source for chemical energy (glucose), the backbone for genetic information (ribose), and the organic constituents of plants (cellulose) or insects (chitin) (D. Voet, J.

G. Voet, Biochemistry, 2nd ed., Wiley, New York, 1995, pp. 251-276). The three- dimensional network of silica and its derived minerals (F. Liebau, Structural Chemistry of Silicates, Springer, New York, 1985, p. 4) results from the condensation of perhydroxylated silicates.

However, very few perhydroxylated boron compounds are known. The most prominent perhydroxylated boron compound is boric acid, B (OH) 3. Alkaline solutions of B (OH) deposit Na [B 0 (OH) J'ntLO, which constitutes two abundant boron minerals, kernite (n=2) and borax (n=8) (F. A. Cotton, G. Wilkinson, Advanced Inorganic Chemist7y, 5th ed., Wiley, New York, 1988, pp. 164-169.). Other common boron structures include the trigonal and tetrahedral boron-oxygen units common to borate minerals, (G. A. Heller, Top. Curr. Chem. 1986,131,39-98), and the B1z-icosahedron.

The allotropes of elemental boron, (J. Donohue, The Structures of the Elements, Wiley, New York, 1974, pp. 48-82) boron-rich solids (H. Hubert, B. Devouard, L. A. J. Garvie,

M. O'Keeffe, P. R. Buseck, W. T. Petuskey, P. F. McMillan, Nature 1998,391,376-378) and the parent anion of the polyhedral boranes, [closo-Bl2Hl2] first reported by Hawthorne et al (A. R. Pitochelli and M. F. Hawthorne J. Am. Chenu. Soc., 1960,82,3228 followed by J. A. Wunderlich, W. N. Lipscomb, J. Am. Chem. Soc. 1960,82,4427-4428) all contain B12 icosahedra.

2- The charge-delocalized icosahedral ion [closo-B 12Hl2] may be considered as the parent aromatic species for borane chemistry in a manner similar to that served by the benzene ring in organic (carbon) chemistry (M. F. Hawthorne, Advances in Boron Chemistry, Special Publication No. 201, Royal Society of Chemistry, London, 1997, pp.

261-272). While benzene and certain other aromatic compounds are known, (ie., phenol, hydroquinone, naphthol) fully hydroxylated aromatic compounds (all-H replaced by-OH) are not known or readily prepared. Contrary to the process described herein for manufacturing hydroxylated borates, no reaction occurs when benzene is refluxed with boiling hydrogen peroxide.

2- Isoelectronic substitution of one or two: B-H vertices in [c/oo-B H] by: C- H+ provides the aromatic derivatives [closo-1-CB11H12]- and a set of three isomeric dicarbacarboranes (1, 2- or ortho ; 1, 7-or meta ; and 1,12-orpara) closo-C2BlOHl2 (R. N.

Grimes, Carboranes, Academic Press, New York, 1970, p. 8). Each of these isoelectronic 2- derivatives of [closo-B12H12] undergoes characteristic hydrogen-substitution reactions at their B-H vertices resulting in a huge number of known icosahedral species.

Of special interest are derivatives in which every available B-H vertex has been 2- substituted. Thus, hydrophobic derivatives of [closo-B12H12] and [closo-1-CB11H12] 2 and the three isomeric dicarbaboranes, such as [closo-Bi2Cl2] (W. H. Knoth, H. C.

Miller, J. C. Sauer, J. H. Balthis, Y. T. Chia, E. L. Muetterties, Inorg, Chem, 1964,3,159- 167), [closo-CB11 (CH3) 121-, (King, B. T.; Janousek, Z.; Gruner, B.; Trammell, M.; Noll, B. C.; Michl, J. J. Am. Chem. Soc. 1996,118,10902-10903), closo-1, 12-C2B10(CH3)12,

(W. Jiang, C. B. Knobler, M. D. Mortier, M. F. Hawthorne, ange. Chem. 1995,107, 1470-1473 ; Angew. Chem. Int. Ed. Eragl. 1995,34,1332-1334) and [closo-Bl2 (CH3) 121' (T. Peymann, C. B. Knobler, M. F. Hawthorne, J. Am. Chem. Soc., 1999,121,5601) have been synthesized.

Additionally, the existence or formulation of similar highly substituted polyhedral borane derivatives having hydrophilic substituents, such as hydroxyl have recently been demonstrated. It was found that per-B-hydroxylated icosahedral borane derivatives, which may be considered to be derivatives of a new type of polyhedral sub-boric acid, can be readily synthesized. The per-B-hydroxylated icosahedral borohydrate compounds, Cs2[closo-B12(OH)12], Cs[closo-1-H-1-CB11(OH)11], and [closo-1, 12-H2-1, 12- 2- C2B10(OH)10] are prepared by the oxidation of the icosahedral boranes [closo-Bl2HIlz], [closo-1-CB11H12]- and [closo-1,12-(CH2OH)2-1,12-C2B10H10], respectively, with excess hydrogen peroxide at the reflux temperature (from about 100°C to 150°C) (Peymann T. et. al., Angew, Chem. Ihd. Ed, 1999,38, No. 8,1062-1063). These compounds and the process to form them are covered by the parent application (09/546, 108 filed April 10,2000) to this application.

The existence of partially substituted compounds, where only 1 to 4 of the B-H vertices are hydroxylated have been used to form ether and ester substituted compounds, with remaining B-H left unsubstituted. However, boron cage compounds, with all the B-H vertices converted to B-OH functions, have not been used to form compounds where some or all of the B-OH vertices are further substituted.

SUMMARY It has now been found that all of the hydroxyl groups on per-B-hydroxylated icosahedral boranes can be readily converted to perether and perester derivatives (including carbamate esters) with the general formulas [closo-Bl2 (OCOR) 12] 2-, [closo- B12 (OR) 12] 2-and [closo-Bl2 (OCONHR)] 2~ where R is an alkyl, alkenyl, alkynyl,

alkenylalkyl, alkynylalkyl, aryl, aralkyl, or a combination thereof. The substituents attached to the B-O groups may contain functional groups for further derivatization reactions ; The perester derivatives are prepared by reacting [Bi2 (OH) l2] 2-or other perhydroxylated cluster species with an organic anhydride or acid chloride, such as acetic anhydride or benzoyl chloride. The percarbamate ester derivatives are synthesized by reaction of [Bi2 (OH) 12] 2- or other perhydroxylated cluster species with isocyanates. The perether derivatives are prepared by reacting [Bl2 (OH) 12] 2- or other perhydroxylated cluster species with various alkylating agents, such as benzyl chloride. Furthermore, the closo-perether derivatives can be oxidized in a step wise manner with iron (III) chloride and other oxidation agents to give mono-anionic and then neutral hypercloso-perether species.

These oxidations are reversible and the corresponding reduction of the hypercloso- perether species can be carried out using sodium borohydride and other reducing agents.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: DRAWINGS FIG. la shows the reaction scheme for the formation of Cs2[closo-B12(OH)12].

FIG. lb shows the reaction scheme for the formation of Cs[closo-1-H-1-CB11(OH)11].

FIG. le shows the reaction scheme for the formation of [closo-1, 12-H2-1, 12- C2B10(OH)10].

FIG. 2 displays an ORTEP diagram of Cs2[closo-B12(OH)12].

FIG. 3 displays an ORTEP diagram of [closo-1, 12-H2-1, 12-C2B10- (OH) J FIG. 4a shows the reaction scheme for the formation of [closo-B12 (OCOCH3) 12] 2-.

FIG. 4b shows the reaction scheme for the formation of [closo-Bl2 (OCOPh) 12] 2-.

FIG. 4c shows the reaction scheme for the formation of [closo-B12 (OCONHPh) l2] 2.

FIG. 5 is an ORTEP diagram of Cs2 [closo-Bl2 (OCOCH3) 1212-,

FIG. 6 displays an ORTEP diagram of [closo-Bl2 (OCOPh)] 2-.

FIG. 7a shows the reaction scheme for the formation of [closo-B12(OCH2Ph)12]2-.

FIG. 7b shows the reaction scheme for the formations of [hypercloso-B12 (OCH2Ph) 12] and [hypercloso-Bi2 (OCH2Ph) 12].

FIG. 8 displays an ORTEP diagram of [closo-Bl2 (OCH2Ph) 12]2- FIG. 9 displays an ORTEP diagram of [hypercloso-B12(OCH2Ph)12].

FIG. 10 displays an ORTEP diagram of [hypecloso-B12 (OCH2Ph) l2].

FIG. 11 displays a space-filling representation of [closo-B12 (OCOPh) 1212- DETAILED DESCRIPTION FIGS. 1 a-c show the synthesis of the perhydroxylated boron cluster species: Cs2 [closo-B12 (OH) 12], Cs [closo-1-H-1-CB11 (OH) 11], and [closo-1, 12-H2-1,12- 2 C2B lo (OH) 10],which are prepared by reaction of the icosahedral boranes [closo-B12H12], [closo-1-CB11H12]- and [closo-1,12-(CH2OH)2-1,12-C2B10H10], respectively, with hydrogen peroxide at its reflux temperature. Hydrogen peroxide (approximately 30% by weight) was used; however, current studies reveal that this concentration may be reduced.

The preferred concentration is between 30% and 5%. The reflux temperature depends on the specific boron compound utilized, its concentration in the reaction mixture and the extent of reaction. (For 30% by weight of hydrogen peroxide the reflux temperature is 2- about 126°C). As shown in FIG. 1 a-c, [closo-B12H12] was refluxed for 4 days and [closo-1-CB11H12]- and [closo-1,12-(CH2OH)21,12-C2B10H10] were refluxed for 15 hours using 30% by weight hydrogen peroxide.

The results of X-ray structure analyses of Cs2[closo-B12(OH)12] and [closo-1, 12- H2-1, 12-C2Blo (OH) lo] are shown in FIGS. 2 and 3, respectively. The sparingly water- soluble salts Cs2 [closo-B12H12] and Cs[closo-1-CB11H12] serve as precursors for Cs2 [closo-Bl2 (OH) 121 and Cs [closo-1-H-1-CB11 (OH) 11], respectively. The synthesis of

[closo-1, 12-H2-1,12-C2B10(OH)10] employs the slightly water-soluble precursor [closo- 1, 12- (CH2OH)2-1,12-C2B10H10], because [closo-1, 12-C2B10H12] is not water-soluble and hence not available to the hydrogen peroxide reagent. During this reaction sequence, the diol [closo-1, 12- (CHOH)-1, 12-C B H], is most likely oxidized to the corresponding dicarboxylic acid which subsequently decarboxylates during B-hydroxylation to provide [closo-1, 12-H2-1,12-C2B10(OH)10].

The yields from the syntheses shown in FIGS. 1 a-c are 80% for [closo-1, 12-H2- 1,12-C2B, o (OH) lo], 65% for Cs2 [closo-B (OH) J and 31% for Cs [closo-1-H-1 CBJOH) J.

The alkali-metal salts of the Cs2 [closo-B12 (OH) 12 1 have a low solubility in water even though its surface is covered with hydroxyl groups. Therefore, Cs2[closo-B12(OH)12] can be recrystallized from water, whereas the Li2, Na2, and K2 salts of [closo- B12(OH)12]2- precipitate quantitatively upon addition of the corresponding alkali metal chloride to warm aqueous solutions of Cs2[closo-B12(OH)12].

The ability to produce Cs2 [closo-Bl2 (OH) 1211 Cs [closo-1-H-1-CB11 (OH) ll] and [closo-1, 12-H2-1,12-C2B10(OH)10], where all the B atoms have an OH group, opens up a new field of boron cluster chemistry, wherein the aromatic icosahedral cluster functions as the scaffolding for reactions that would be performed on its oxygen sheathing. For example, Cs2[closo-B12(OH)12] can be used as the central core for the formation of multioligomeric organic and inorganic compounds similar to dendrimers (G. R. Newkome, C. N. Moorefield, F. Vögtle, Dendritic Molecules, VCH, New York, 1996, showing dendrite molecules derived from much different compounds resulting in structures with the oligomeric chains emanating from single atoms rather then a molecular surface).

Furthermore, it is believed that the high temperature pyrolysis of a simple salt of Cs2[closo-B12(OH)12] might form a polymeric network of very stable icosahedral clusters connected by covalent B-O-B bonds. Species of this sort are expected to be chemically inert due to strong B-O bonds. However, the polymeric array of dianionic cages is expected to serve as a source of electrons for chemical processes while still retaining

water solubility. In addition, the possibilities of the covalent incorporation of species, such as Csc/Mo-B (OH)], in metal oxide lattices are boundless.

The present invention is primarily directed to the synthesis of newly defined closomers derived from [closo-Bl2 (OH) 12] 2- in which each hydroxyl function is converted into a carboxylate ester or ether group. (Closomers are cage polyhedra structures whose surfaces support polyatomic substituents. The word"closomer"comes from the root "closed", and denotes a closed polyhedral cage structure, where all faces of the polyhedra have an approximately similar geometry, as distinguished from open structures like nido or arachno structures.) Although specific examples employing closomers are used, one skilled in the art will readily recognize that the same principle can equally apply to other boron cage structures such as nidomers and arachomers. (see"Carboranes", R. N. Grimes, Academic Press, New York, 1970).

The formulation n (m)-closomers is used, where"n"indicates the total number of cluster vertices potentially available for substitution and"m"refers to the number of attached substituents. For example, the designation 12 (12)-closomers indicates a polyhedron containing 12 vertices and 12 substituents.

PreferredProcedure It has now been found that dodecahydroxy-closo-dodecaborate (2-) ( [B12 (OH) 12] 2) can be reacted with anhydrides, acid chlorides, or isocyanates (for carbamate esters) to produce dodecaester derivatives, in which each hydroxyl group is converted into an ester function.

FIGS. 4a-c show reaction schemes for the formation of various, representative esters of Cs2 [closo-B, 2 (OH) 121. The dodecaacetate ( [closo-B12 (OCOCH3) l2] 2-) (FIG. 4a) was formed in 43% yield by reaction of Cs2 [closo-Bl2 (OH) 121 with acetic anhydride ((CH3CO) 20) at the reflux temperature for 3 days. Cs2 [closo-Bl2 (OCOCH3) l2] is soluble in water and methanol and moderately soluble in acetonitrile and acetone. The 11B NMR spectrum of Cs2[closo-B12(OCOCH3)12] shows a symmetrical singlet at-16 ppm which is not significantly different from that of the starting material, Cs2 [closo-Bl2 (OH) l2]. If the esterification reaction does not proceed to completion the 11B NMR spectrum of the partly

esterified [closo-Bl2 (OH) 12-n (OAc) n] 2- (where n = 1-11) appears as an asymmetric signal resulting from the reduced symmetry of the B12-icosahedron. In this case, the reaction with acetic anhydride can be continued to complete the esterification of all twelve hydroxyl functions. The 1H NMR spectrum of Cs2 [closo-Bl2 (0COCH3) l2] exhibits a singlet at 1.9 ppm for the methyl protons; the'3C NMR spectrum displays a signal at 174 ppm for the carbonyl functions and a signal at 22 ppm for the methyl groups. The electrospray mass spectrum (negative mode) reveals the molecular ion peak (mlz) of [closo- B12 (OCOCH3) i2] 2 at 839.2 for [ [closo-Bl2 (OCOCH3) 12] 2-+H]-, and a peak for the dinegatively charged cluster, [closo-B12 (OCOCH3) 1212-, at 419. 1.

FIG. 5 is an ORTEP diagram showing the result of single-crystal X-ray structure analysis performed with Cs2[closo-B12(OCOCH3)12]2-. The central cluster is made up entirely of boron atoms. The open circles on the outer ends of the structure are hydrogen atoms. (Although all of the atoms are not labeled for simplicity, one skilled in the art will readily recognize the identity of each of the atoms based on the description herein).

Dianion [closo-Bl2 (OCOCH3) 1212- is centrosymmetric and the B12-cage has approximate icosahedral symmetry with B-B bond distances ranging from 1.776 (3) A to 1.843 (3) A and B-0 bond lengths of 1.440 (2) A to 1.449 (2) A.

An important requirement for the success of the closomer esterification reaction is the dissolution of the [closo-Bl2 (OH) 12]2- ion reactant. The solubility of the closo- compound is dependent upon the identity of the cations employed. The dicesium salt, Cs2 [closo-Bl2 (OH) 12], is moderately soluble in water. It is only partially soluble in carboxylic acid anhydrides containing short carbon chains, such as acetic or propionic anhydrides at elevated temperatures. Conversion of the Cs2 salt into the [Bu4N]2 salt increases the solubility of [closo-B12(OH)12]2- in organic solvents and enables the synthesis of carboxylate esters from acid chlorides in 1,2-dichloroethane or acetonitrile at their reflux temperatures.

Reaction of [NBu4] 2 [closo-Bl2 (OH)12] with an excess of benzoyl chloride in the presence of triethylamine in acetonitrile gave the dodecabenzoate ester ([closo- B12 (OCOPh) 12] 2-) in 52% yield following a reaction time of 10 days (FIG. 4b). The electrospray mass spectrum of [closo-Bl2 (OCOPh) i2] in the negative mode reveals a

peak (mlz) at 1584.0 for [[closo-Bl2 (OCOPh) 12]2-+H]- and 791.5 for [closo- Bl2 (OCOPh) 12]2-. Suprprisingly, the electrospray mass spectrum in the positive mode does not indicate the presence of equivalent amounts of the cations expected for [closo- B12 (OCOPh) 12]2-. The data reveal a significant disparity in the signal strengths of the observed negative ions when compared with the observed positive ions of the same sample. The signal strengths in the negative ion mode for [closo-Bl2 (OCOPh) 1212- and [[closo-Bl2 (OCOPh) la] 2-+H]-relative to the cations observed in the positive ion mode was estimated from the ratio of signal intensities obtained in the two modes under identical scanning and detector settings with the same solution and in the absence of reagents that might enhance ion intensities in either mode, and assuming similar ionization efficacy for positive and negative ions. For a salt with the composition AB2 (where"A"is an anion and "B"is a cation) the signal intensities for the negative and the positive ions are expected to be equivalent to the ratio of 1 to 2. The measured signal intensities of anions and cations in the same sample reveal only a ratio of about 1 to 0.18.

The'H and 13C NMR data of [closo-B12 (OCOPh) 12] 2- display the signals expected for [closo-Bl2 (OCOPh) 12]2- alone, while the"B NMR spectrum shows a. symmetrical singlet at-16 ppm. Based on the mass spectrometry and NMR data, which both lack the presence of a detectable cation in amounts equivalent to [closo-B12 (OCOPh) 12] 2-, it is believed that the dodecabenzoate [closo-Bl2 (OCOPh) 12]2- was isolated in its diprotonated form as [H] [closo-B12(OCOPh)12] or as a dihydronium salt, [H3O]2[closo-B12(OCOPh)12]. This is supported by the existence of a weak signal in the electrospray mass spectrum in the positive mode at m/z = 1586 for [ [closo-B12 (OCOPh) 12] 2-+3H] +. The existence of this positive closomer ion indicates that the multiple protonation of [closo-Bl2 (OCOPh) 12] 2- is indeed possible. At the present time it was not ascertained whether [closo- B12(OCOPh)12]2- was isolated as [H] 2 [closo-Bl2 (OCOPh) 121 or [H3O]2[closo- B12 (OCOPh) 12], but for simplicity it is assumed to be the dihydronium salt, [H30] 2 [closo- B12 (OCOPh) 12]. This species was presumably formed during the chromatographic purification of [closo-Bl2 (OCOPh) 12] 2- on silica gel by interaction of [closo- B12 (OCOPh) 12]2- with proton sources associated with the silica. The species assumed to

be [H30] 2 [closo-Bl2 (OCOPh) 12] is soluble in dimethylsulfoxide and dimethylformamide and poorly soluble in acetonitrile and methanol.

Addition of tetraphenylarsonium chloride to a solution of [H30] 2 [closo- B12 (OCOPh) 121 in dimethylformamide gave [Ph4As] 2 [closo-Bl2 (OCOPh) 12] as a white solid which is readily soluble in methanol and acetonitrile. FIG. 6 displays the result of an X-ray structure analysis performed with. [Ph4As] 2 [closo-Bl2 (OCOPh) 12]. Again, for simplicity, the atoms are not all labeled. The ion [closo-BI2 (OCOPh) 12] 2- is centrosymmetric with approximate icosahedral symmetry in the B12-cage ; the B-B distances range from 1.768 (4) to 1.828 (4) A and the B-O distances from 1.416 (3) to 1.429 (3) A. FIG. 11 is a space-filling representation of [closo-B12(OCOPh)12]2- displaying the impressive camouflage of the dinegatively charged B12-cluster by the twelve benzoate groups which almost completely cover its icosahedral surface.

In addition to the described perester derivatives the synthesis of percarbamate ester derivatives has been accomplished. The reaction of [NBu4] 2 [closo-B12(OH)12] with excess phenylisocyante in dichloroethane or acetonitrile affords the percarbamate ester derivative [closo-Bl2 (OCONHPh) l2] 2~ (FIG. 4c). These reactions are more fully described in the examples below. One skilled in the art will recognize that other esters (including carbamate esters) having the general formula [closo-Bl2 (OCOR) 12] 2- (or [closo- B12 (OCONHR) 12] for carbamate esters), where R is an alkyl, alkenyl, alkynyl, alkenylalkyl, alkynylalkyl, aryl, aralkyl, or a combination thereof, can be formed using standard esterification agents known in organic chemistry.

While the synthesis of esters employing acid anhydrides, acid chlorides or isocyanates (for carbamate esters) are well known organic reactions, it is unexpected that this simple chemistry will provide the novel 12 (12)-closomer esters described herein with all hydroxyl groups in [closo-Bl2 (OH) 12] 2- converted into ester functions leading to total organoderivatization of its icosahedral surface. The resulting fully substituted boron cage compounds, such as the 12 (12)-closomers, with each cluster vertex substituted by an organic ester moiety, represents the first examples of this structural motif in chemistry.

In addition to the synthesis of closomeric perester derivatives, the synthesis of perether derivatives was achieved. FIGS. 7a and b show the synthesis of perether

derivatives, exemplified in the preparation of [closo-B12(OCH2Ph)12]2- by the per-O- benzylation of [closo-Bl2 (OH) 12] 2- (shown in FIG. 7a). Also shown are the reversible one electron oxidation reactions of [closo-B12 (OCH2Ph) i2] 2 with iron (III) chloride to produce mono-anionic paramagnetic [hypercloso-Bl2 (OCH2Ph) 12] and neutral [hypercloso- B12 (OCH2Ph) 121 (shown in FIG. 7b).

Theneutral hypercloso-Bl2 (OCH2Ph) l2is a novel electron-deficient hypercloso species, [closo-B12 (OCH2Ph) 12], and the first characterized derivative of hypercloso-B12H12.

Although the hypereloso-Bl2Hl2 has not been synthesized, it has been the subject of numerous computational studies. (M. L. McKee, Z.-X. Wang, P. v. R. Schleyer, J Am.

Chem. Soc. 2000,122,4781-4793, and references cited therein).

The anion [closo-Bl2 (OH) 12] 2- Bis (Phosphoraneylidene) ammonium ("PPN") salt was per-O-benzylated in acetonitrile solution at the reflux temperature employing benzyl chloride in the presence of diisopropylethylamine (FIG. 7a). After a reaction time of six days the salt Na [PPN] [closo-Bl2 (OCH2Ph) l2], was obtained in 48% isolated yield. During the product isolation procedure sodium borohydride was added to reduce spurious amounts of the radical species [closo-Bl2 (OCH2Ph) 121'- formed during the reaction.

Prolonged reaction times led to lower yields of [closo-B12 (OCH2Ph) 12] 2-, presumably due to the decomposition of paramagnetic [hypercloso-Bl2 (OCH2Ph) 121*- produced via the oxidation of [closo-Bl2 (OCH2Ph) 12] 2- with excess benzyl chloride. Shorter reaction times, on the other hand, led to decreased yields because of the incomplete conversion of [closo- B12 (OH) 12] 2- to [closo-B12(OCH2Ph)12]2-. An electrospray mass spectrometry signal (m/z) of 708.2 (100%) is observed for the dinegative ion [closo-B12(OCH2Ph)12]2-. In the positive mode, signals ascribed to the two cations, Na+ and PPN+ are observed. The"B, 1H, and 13C NMR data confirm the icosahedral symmetry of species [closo- B12 (OCH2Ph) 12] 2-. The UV-visible spectrum of K2 [closo-B12 (OCH2Ph) 12], obtained by metathesis of Na [PPN] [closo-Bl2 (OCH2Ph) 121, has absorption bands at 210 nm (6. 8x104), 233 nm (2. 1x104) and 260 nm (6x103).

Figure 8 depicts the solid state structure of [closo-Bl2 (OCH2Ph) 12] 2- determined by an X-ray diffraction study of Cs [PPN] [closo-B12(OCH2Ph012] (obtained by conversion of the Na [PPN] salt to the Cs [PPN] salt through cation exchange). The cage of dianion

[closo-Bl2 (OCH2Ph) 121'-has icosahedral symmetry with the B-B bond distances covering the narrow range of 1.781 (4) to 1.824 (4) A and B-O bond lengths of 1.434 (3) to 1.451 (3) A. Salts of anion [closo-Bl2 (OCH2Ph) 12] 2- slowly air-oxidize and develop a purple tint upon exposure to air due to the formation of [closo-B12(OCH2Ph)12].

Chemical one-electron oxidation of [closo-Bl2 (OCH2Ph) 12] 2- employing FeIII afforded the purple, paramagnetic monoanion [closo-B12(OCH2Ph)12] as its PPN+ salt in 90% yield (FIG. 7b). A broad (200 Gauss) EPR signal with g = 2.1997 was observed with [PPN] [closo-Bl2 (OCH2Ph) 12]. Negative-ion electrospray mass spectrometry of [PPN] [closo-B12 (OCH2Ph) 121 gave a peak (m/z) at 1416.0 (100%) corresponding to the formulation [hypercloso-B12 (OCH2Ph) 12]-. The visible spectrum of [PPN] [closo- B12 (OCH2Ph) 121 in acetonitrile solution exhibits an intense band in the visible region at 537 nm (1. 4x104) accompanied by strong absorption in the UV due to the presence of benzyl groups. The crystal structure of [PPN] [closo-Bl2 (OCH2Ph) 12]#C6H6 confirms the monoanionic nature of [closo-Bl2 (OCH2Ph) 121*-.

Compared with [closo-BI2 (OCH2Ph) 12] 2-, the boron cage of species [closo- B12 (OCH2Ph) 121*- has a higher distortion from icosahedral symmetry as the B-B bond distances (1.768 (4)-1.840 (4) A) are slightly lengthened and the B-O distances (1.398 (3)- 1.419 (3) A) are shortened by about 0.03A.

The sequential two-electron oxidation of [closo-B12 (OCH2Ph), l2] 2- [cl, oso- B12 (OCH2Ph)12]-, with Fe in ethanol affords [closo-B12 (OCH2Ph) 12] as a dark-orange solid (Scheme 7b). The purple anion-radical [hypercloso-B12 (OCH2Ph) 121'-, is observed as an intermediate in this overall reaction. An ion at m/z of 1415.8 (100%) assigned to the formula [B12(OCH2C6H5)12]- is recorded for [closo-Bl2 (OCH2Ph) 121 by fast atom bombardment mass spectrometry. The 11B NMR spectrum of [closo-B12 (OCH2Ph) 121 exhibits a singlet at 43.3 ppm, a downfield shift of 58 ppm relative to the singlet observed at-14.8 ppm for dinegative [closo-B12 (OCH2Ph) 12]2-. The 1H and 13C NMR spectra exhibit broad signals, probably due to paramagnetic impurities or spurious reduction of [closo-B12 (OCH2Ph) 121 to [closo-B12 (OCH2Ph) 121.- in solution. The visible spectrum of orange [closo-B12 (OCH2Ph) 121 in acetonitrile solution exhibits a strong absorption at 467

nm (1. 7x104). A crystal of [closo-B12 (OCH2Ph) 121 suitable for X-ray diffraction studies was obtained from acetonitrile solution (ORTEP diagram shown in Figure 10). Most importantly, the solid state structure of [closo-Bl2 (OCH2Ph) l2] reveals a hypercloso borane cage with only approximate icosahedral geometry (D3d). A detailed analysis of the bonding parameters demonstrates this departure from icosahedral symmetry. Notably, the B-B distances observed in [closo-B12 (OCH2Ph) 12] are in the broad range of 1.755 (2) to 1.918 (2) A and should be compared with the corresponding distances of 1.781 (4)-1. 824 (4) A in [closo-B12(OCH2PH)12]2- and 1.768 (4)-1. 840 (4) A in paramagnetic anion [closo -B12(OCH2PH)12]. Conspicuously, the B-0 distances observed in [closo- B12 (OCH2Ph) 121 ([closo-B12(OCH2PH)12] : 1.369 (2)-1. 404 (2) A ; [closo-B12 (OCH2Ph) l2] ~ : 1.434 (3)-1. 451 (3) A ; and [closo-Bl2 (OCH2Ph) 12] : 1.398 (3)-1. 419 (3) A]) are shortened by about 0.06 A with respect to [closo-BI2 (OCH2Ph) 12] 2- and by about 0.02A relative to [closo-B12(OCH2PH)12]-.

A more detailed examination of the distorted icosahedral geometry of [closo- B12 (OCH2Ph) 12] reveals that the six longest B-B bonds [B-B = 1.910 (2)-1. 918 (2) A] are located in two opposing symmetry-related boron triangles: B4, B5, B2' and B4', B5', B2.

The remaining shorter B-B bond lengths [1.755 (2)-1. 864 (2) A] are similar to those observed in [closo-Bi2 (OCH2Ph) i2] 2- and [closo-Bl2 (OCH2Ph) 12]-. The B-O bond distances of [closo-Bl2 (OCH2Ph) 121 may be divided into two groups as well. The six shorter B-O bond lengths [1.369 (2)-1. 378 (2) A] are associated with the oxygen atoms attached to the boron vertices of the elongated triangles. The six longer B-O bonds [1.398 (2)-1. 404 (2) A] are associated with the remaining boron vertices. All B-O-C bond angles deviate from the ideal Sp3 bond angle by more than 10°. The bond angles associated with the shorter B-O bonds [123. 2 (1)-123. 4 (1) A] are about 2° larger than the corresponding angles about the oxygen atoms of the longer B-0 bonds [121.5 (1)-121. 7 (1) AI.

The distorted icosahedron of [closo-B12(OCH2PH)12] has approximate D3d symmetry with the C3 axis penetrating the centers of the elongated triangles: B4, B5, B2' and B4',B5',B2 (see FIG. 10). Previously, neutral B12 clusters structurally similar to the distorted icosahedron of [closo-B12 (OCH2Ph) l2] have been observed in elemental boron.

In 0-rhombohedral boron, three structural types of B12-clusters are present (J. Donohue, The Structures of the Elements, Wiley, New York, 1974, pp. 48-82). One of these icosahedra displays D3d symmetry with two triangular faces having elongated edges (long B-B bonds = 1.801 A, short B-B bonds = 1.751-1.767 A). Furthermore, a distorted icosahedron with D3d symmetry has been identified as an energy minimum in computations carried out on an HF/6-31G (d) level for [hypercloso-B12H12] (M. Fujimori, K. Kimura, J.

Solid State. Chem. 1997, 133, 178-181). An undistorted icosahedral [hypercloso-B12H12] structure would have partially occupied fourfold degenerate Higher Order Molecular Orbitals (HOMOs). A Jahn-Teller distortion to the observed D3d structure removes this degeneracy.

In a comparison of the structures of the per (benzyloxy) icosahedral boranes [Bl2 (OCH2Ph) 12]n-, (n = 0-2), it becomes apparent that the range of B-B bond distances widens with a decrease in the number of skeletal electrons. On the other hand, the B-O bond distances shorten concomitantly with the loss of cluster electron density. Relative to [closo-B12 (OCH2Ph) 12] 2- and [closo-B12(OCH2Ph)12]#-, the shorter B-O bond lengths of [closo-B12 (OCH2Ph) 121 suggest the presence of considerable double bond character attributed to enhanced s-backbonding of the ex-oxygen atoms to the electron-deficient hypercloso-icosahedron of [closo-BI2 (OCH2Ph) 121, Indeed, the shortest B-O bonds of [closo-B12 (OCH2Ph) 12] are associated with those oxygen atoms attached to the more electron-poor boron triangles: B4, B5, B2' and B4', B5', B2 having the longest B-B bonds.

The redox chemistry of [closo-B12 (OCH2Ph) 121 was studied by cyclic voltammetry. The cyclic voltammogram of [closo-B12(OCH2Ph)12] [100 mM N (n- Bu) 4PF6, Ag/AgCl, acetonitrile] shows reversible one-electron transfer processes with Ei/2 = 0.46 and 0.0 V which are attributed to the two couples [closo-B12 (OCH2Ph) 12]/ [closc- B12(OCH2Ph)12]#- and [closo-B12(OCH2Ph)12]#-/[closo-B12(OCH2Ph)12]2-, respectively.

Based on the teachings herein, one skilled in the art will recognize that other ethers, having the general formula [closo-Bl2 (OR) i2] 2- (where R is an alkyl, alkenyl, alkynyl, alkenylalkyl, alkynylalkyl, aryl, aralkyl, or a combination thereof) can be formed using various different reagents commonly used for the formation of ethers.

Experimental Procedure: Solvents and liquid reagents were dried and distilled according to standard procedures. All reactions were carried out under moisture free conditions using argon as the inert gas. NMR spectra were obtained on a Bruker ARX 500 spectrometer, electrospray mass spectra on a Perkin-Elmer Sciex API triple quadruple mass spectrometer and fast atom bombardment (FAB) mass spectra were obtained on a VG SAB-SE mass spectrometer.

Example 1 Synthesis of rcloso-B-) (OCOC 912-FIGS. 4a and 5) : A suspension of Cs2 [closo- B12 (OH) 121 (48 mg, 0. 080 mmol) in 6 ml of acetic acid anhydride was heated with stirring at the reflux temperature for 3 days under argon. The brown reaction mixture was cooled to room temperature and the volatiles removed in vacuo. The residue was dried in vacuo at 50°C for 10 hours. The solid was dissolved in 6 ml of room temperature water, the solution filtered and the filtrate cooled at 3°C for 60 minutes. The obtained suspension was again filtered through 0.2 ßm filter, and the water removed in vacuo to give Cs2 [closo- B12 (OCOCH3)12] as a light brown solid in sufficient purity (38 mg, 0.034 mmol, 43% yield). Further purification can be achieved by recrystallization from acetic anhydride.

Single crystals of Cs2 [closo-Bl2 (OCOCH3) i2] x 2SC (NH2) 2 suitable for X-ray structure analysis were obtained from a solution in acetonitrile/water with the addition of a small amount of thiourea (thiourea was added to improve crystal growth). Table 1 lists the data obtained for the NMR and electrospray mass spectrum of Cs2 [closo- Bl2 (OCOCH3) l2] : 1H NMR [ppm] 1. 9 (Me) (500 MHz, D2O) 13C NMR [ppm] 22.0 (Me) 174.0 (CO) (126 MHz, D20) "BNMR [ppm]-16 (160 MHz, D20)

839.2 ([[closo- 419.1[closo-B12(OCOCH3)12]2 ESI-MS (m/z) B12 (OCOCH3) 12]2-+H])- (negative mode, water) Table 1 X-ray data for the Cs2[closo-B12(OCOCH3)12] x 2SC(NH2)2 crystal is shown in Table 2 : crystal system triclinic space group P-1 lengths [A] a= 10.953 (6), b = 11. 334 (7), c = 11.532 (7) angles [°] a=91.918 (11), ß=113. 221 (9), y= 112.575 (9) Volume [Å3] 1185.6 (12) 'xi Table 2 Data were collected on a Bruker SMART 1000 using MoKa radiation (2oman = 56°) giving 5436 unique reflections and the structure was solved by direct methods. The final discrepancy index was R = 0.020, Rw = 0.048 for 4914 independent reflections with I> 2 (cs (I)). Crystallographic data (excluding structure factors) have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC- 151203. Copies of the data can be obtained free of charge on application to CCDC, 12

Union Road, Cambridge CB21EZ, UK (Fax: (+44) 1223-336-033, E-mail: deposit@ccdc. cam. ac. uk).

Example 2 Synthesis of [closo-B12(OCH2Ph)12]2- (FIGS. 4b and 6) : To a suspension of (NBu4) 2 [closo- B12 (OH) 121 (47 mg, 0.058 mmol) in 30 ml dry acetonitrile were added 0.4 ml of benzoyl chloride (484 mg, 3.5 mmol) and 2 ml of dry triethylamine (1.452 g, 14.3 mmol). The reaction mixture was heated with stirring at the reflux temperature for 10 days under argon. The brown suspension was cooled to room temperature, filtered and the volatiles were removed in vacuo. The resulting dark brown solid was purified by filtration over silica gel initially employing CH2C12, followed by THF and finally acetonitrile as the mobile phases. The first two mobile phases eluted colored impurities and elution was continued until the elute was colorless. The mobile phase was then changed to acetonitrile. The acetonitrile fractions were collected, the solvent was removed in vacuo and the solid was washed with THF and warm water to give pure [H3012 ( [closo-BI2 (OCOPh)] 2-) as a white solid (49 mg, 0.030 mmol, 52%).

Table 3 lists the data obtained for the NMR and electrospray mass spectrum: 'H NMR [ppm] 8.0 (m, 24 H) 7.4 (m, 12 H) 7.1 (m, 24 H) (500 MHz, [D6]-DMSO) C NMR [ppm] 22.0 (Me) 163.6 (CO), (126 MHz, [D6]-DMSO) 134.7,130.7, 130.1,127.2 "B NMR [ppm]-16 (160 MHz, [D6]-DMSO) ESI-MS (m/z) 1584.0 ([[closo- 791. 5 ([closo- (negative mode, B12 (OCOPh)] 2-+H]-) B12 (OCOPh)] 2-) acetonitrile) Table 3 X-ray data for [H3O]2[closo-B12(OCOPh)] is shown in Table 4 :

crystal system: Triclinic space group: P-1 lengths [A] a= 13.873 (2), b = 15.680 (2), c = 16.280 (2) angles [°] α=65. 368 (2), ß= 66.727 (2), y= 80.638 (2) Volume [Å3] 2957. 2 (7) 'zu Table 4 Data were collected on a Bruker SMART cod diffractometer using MoKa radiation (26max = 56.6°) giving 13554 unique reflections and the structure was solved by Patterson and heavy atom methods. The final discrepancy index was R = 0.054, Rw = 0.159 for 7763 independent reflections with I > 2 (a (I)). Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC- 151204. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Fax : (+44) 1223-336-033, E-mail: deposit@ccdc. cam. ac. uk).

Example 3 Synthesis of [closo-B12(OCONHPh)12]2- (FIG. 4c): To a suspension of 40 mg (0. 090 mmol) [NBu] 2 [BI2 (OH) 12] in 10 ml dry 1, 1-dichloroethane were added 5 ml of phenylisocyanate and the mixture stirred for 6 days at 60 degrees C under argon. The volatiles were removed in vacuo and the residue washed with a mixture of diethyl ether and hexane in a 1 to 1 ratio. The remaining residue was suspended in a mixture of ethyl acetate and hexane in a 2 to 1 ratio, filtered, and the solvent removed in vacuo to give [NBu] 2 [closo-Bl2 (OCONHPh) i2] as a crude product.

Table 5 lists the data obtained for the NMR and electrospray mass spectrum of [NBu] 2 [closo-B12(OCONHPh)12]: 11B NMR [ppm] (160 MHz,-16 acetonitrile) ESI-MS (m/z) 1763.0 ([[closo-B12(OCONHPh)12]2-+H]-) (negative mode, acetonitrile) Table5 Example 4 Synthesis of [closo-B12(OCH2Ph)12]2- (FIGS. 7a and 8) Na[PN] [closo-B12(OCH2Ph)12]: An acetonitrile solution (15 ml) of [PPN] 2 [B12 (OH) 12] (0.60 g, 0.43 mmol), diisopropylethylamine (0.89 ml, 5.1 mmol), and benzyl chloride (2.9 ml, 26 mmol) was heated at the reflux temperature for 6 days under nitrogen. All volatile materials present in the purple reaction mixture containing [closo-Bl2 (OCH2Ph) 121*- were removed in vacuo and ethanol (20 ml) was added. The resulting suspension was kept at - 18 °C overnight and a grayish-purple solid was removed by filtration. This solid was dissolved in warm ethanol and sodium borohydride (0.04 g, 1 mmol) was added to decolorize the suspension by reducing [closo-Bl2 (OCH2Ph) 121*- to [closo-B12(OCH2Ph)12]2.

The solvent was removed in vacuo and the residue extracted with acetonitrile. The extracts were combined and evaporated to produce a residue which was recrystallized from ethanol. After seven days at-18 °C, crystals were obtained (having a melting point >250 °C), which were collected by filtration to yield Na [PPN] [closo-Bl2 (OCH2Ph) 121 (0.40 g, 0.20 mmol, 48% yield).

Table 6 lists the data obtained for the NMR and electrospray mass spectrum of Na [PPN] [closo-B12 (OCH2Ph) 121 : 11B NMR[ppm]-14.8 (160 MHz, acetone):

1H NMR [ppm] 7.60-7.52 (m, 7.38-7.02 (m, 60 5.57 (s, 24 (400 MHz, 30H, Ph, PPN+), H, CH2Ph) ; H, CH2Ph) [D8]acetone): 13C NMR [ppm] 145.8 (C1, 127. 2,126.7 (2 C2,125.0 (C4,68.3 (400MHz, CH2Ph) ; 2 C3, CH2Ph), (C4, CH2Ph) (CH2Ph) [D8] acetone) CH2Ph) ESI-MS (m/z) 708.2 (MeCN) (negative mode) ( [Na [PPN] [closo- B12 (OCH2Ph) 12]]) ESI-MS (m/z) 22.7 (50) ([Na]+) 63.8 (95) ( [Na + 104.9 (70) 539.0 (100) (positive mode) MeCN] +) ( [Na + 2 [PPN]" MeCN] +) Table 6 K2[closo-B12(OCH2Ph)12]2- To a warm ethanol solution (10 ml) of Na [PPN] [closo- B12 (OCH2Ph) 121 (350 mg, 0.18 mmol) was added a solution of CH3COOK (350 mg, 3.57 mmol) in ethanol (5 ml). The mixture was kept at-18 °C for one week. Crystals separated which were separated by filtration and dried to yield K2[closo-B12(OCH2Ph)12]2- (260 mg, 0.17 mmol, 94%). Table 7 lists the results of the NMR and UV/VIS : 1H NMR spectroscopy no PPN+ resonance observed. UV/VIS (MeCN) k (s) 210 (6. 8x104), 233 (2. 1x104), 260 mu (6x103).

Table 7 The X-ray data for Cs [PPN] [closo-B12 (OCH2Ph) 12] are listed in table 8: crystal system: triclinic space group: P-1 lengths [A] ex= 9. 986 (2), b = 14.039 (3), c = 18.441 (4) angles [°] a= 90. 062 (4), (3 = 93.348 (3), y = 90.238 (4) Volume [Å3] 2580. 6 (8) z 1 Table8

Data were collected on a Bruker SMART 1000 using MoKa radiation (26maux = 56.6°), p = 1.343 Mgm3, #(MoKα)=0. 71069 A, 100 K. Of the 11868 unique reflections measured, 7291 were considered observed [I>26 (l)]. Data were corrected for Lorentz and polarization effects but not for absorption, p, = 0.455 mm 1. The structure was solved by statistical methods. R = 0.042, wu = 0.065. Crystallographic data (excluding structure factors) for the structure reported have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-148659. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Fax: (+44) 1223-336-033, E-mail: deposit@ccdc. cam. ac. uk).

Example 5 Synthesis of [hypercloso-B12(OCH2Ph)12]#- (FIGS. 7b and 9) [PPN] [hypercloso-B12 OCH2Ph)12]: To a solution of Na [PPN] [closo-Bl2 (OCH2Ph) l2] (100 mg, 0.050 mmol) in warm ethanol (10 ml) was added an ethanol solution (5 ml) of FeCl3 6H20 (14 mg, 0.050 mmol). The purple reaction solution was stirred for 30 minutes at 25 °C and then kept at-18 °C for 3 hours. Dark-purple crystals precipitated which were separated by filtration, recrystallized from ethanol (melting point = 197 °C), and dried to yield [PPN] [closo-Bl2 (OCH2Ph) 121 (90 mg, 0.046 mmol, 90%).

Table 9 lists the data obtained for the NMR and electrospray mass spectrum of Na [PPN] [closo-B iz (OCH2Ph) 12] : ESI-MS (m/z) (MeCN, negative mode) 1416.0 (100) ([hypercloso-B12(OCH2Ph)12]-). VIS (MeCN) (s) [nm] 537 (1.4x104) EPR (solid, 273 K) [g] 2.1997 Table 9 The X-ray data for [PPN] [closo-B12 (OCH2Ph) 12]#C6H6are listed in table 10:

crystal system: triclinic space group: P-1 lengths [A] a = 17.761 (8), b = 18.786 (8), c = 20.588 (9) angles [°] a 65.156 (7), ß = 65.725 (8), y = 63.417 (8) Volume [Å3] 5360 (4) 2 Table 10 Data were collected on a Bruker SMART 1000 using MoKa radiation, 2Fax = 56.66°, p = 1.259 Mgm-3, #(MoKα) = observed, [P2 (l)]. Data were corrected for Lorentz and polarization effects but not for absorption, p, = 0.106 mm-1. The structure was solved by statistical methods. R = 0.073, wR = 0.186. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no.

CCDC-148660. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Fax: (+44) 1223-336-033, E-mail: deposit@ccdc. cam. ac. uk).

Example 6 Synthesis of [hypercloso-B12(OCH2Ph)12] (FIGS. 7b and 10) : A sample of K2 [closo- B12 (OCH2Ph) 121 (100 mg, 0.067 mmol) was dissolved in 10 ml of ethanol and an ethanol

solution (5 ml) of FeCl3 6H20 (45 mg, 0.166 mmol) was added. The reaction mixture turned purple and then dark red. The suspension was stirred for 1 h at room temperature and the precipitate was removed by filtration. The orange-brown solid was recrystallized from ethanol (mp = 155 °C) to give [closo-B12(OCH2Ph)12] (80 mg, 0.057 mmol) in 84% yield.

Table 11 lists the data for the NMR, VIS, and FAB spectrum: FAB MS (Acetone) 1324.7 (25) 1415.8 (100) ( [closo-1506. 7 (70) (m/z) (negative mode) [[hypercloso- B12(OCH2Ph)12]-), ([closo- B12 OCH2Ph)12] B12 (OCH2Ph) 12[ -CH2Ph]- + CH2Ph]-) 11B NMR [ppm] (160 43. 3 MHz, acetone) VIS X (s) [nm] 467 (1. 7x104) (MeCN) : Table 11 An ORTEP diagram of [closo-Bl2 (OCH2Ph) 12] hypercloso-B12 (OCH2Ph) 121 is shown in FIG. 10. The X-ray data is listed in Table 12: crystal system Triclinic space group P-1 lengths [A] a = 10. 107 (3), b = 15.014 (4), c = 15.033 (4) angles [°] a = 114.893 (4), ß = 118.28 (2), y = 102.823 (5) Volume [A] 1880.8 (9) Z 1 Table 12

Data were collected on a Bruker SMART 1000 using MoKa radiation, 26max = 56.66° p (Mgrn3) =1.25, B (MoKa) = 0.71069 A, 100 K. Of the 11869 unique reflections measured, 8403 were considered observed, [I>2cs. Data were corrected for Lorentz and polarization effects, but not for absorption, u = 0.079 mm \ The structure was solved by statistical methods. R = 0.048, wR = 0.118. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC- 148658. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Fax: (+44) 1223-336-033, E-mail: deposit@ccdc. cam. ac. uk).

Potential applications Of particular significance, it is now possible to form fully organofunctionalized derivatives of the dodecaborate, [closo-Bl2OHl2] 2', and then incorporate the dodecaborate cluster in numerous new compounds using typical reactions of esters and ethers. The total functionalization of the B12 icosahedron produces the core of closomers. These closomers may have linear or branched substituents which can be monomeric or oligomeric. The closomeric structures provide camouflaged modules of variable size, shape, charge, hydrophobicity, etc. designed to accomplish a huge variety of functions.

Applications of the closomeric species described herein include: 1. The 12 (12)-closomers, their esters, ethers and derivatives thereof, can be used as drug delivery vehicles. Biological active substrates, such as chemotherapeutic agents and tumor targeting moieties, amongst others, can be added to the multiple ester and ether attachment sites; 2. New closomeric gadolinium perchelates for use as contrast agents for magnetic resonance imaging (MRI) can be formed; 3. Globular amphiphiles for the development of artificial nanostructures, such as artificial lipids and membranes can be formed; 4.12 (12)-closomers substituted with multiple copies of antigenic peptides for the production of antipeptide antibodies and synthetic vaccines can be synthesized;

5. Carbohydrate-containing 12 (12)-closomers for enhanced carbohydrate-protein interactions can be synthesized; 6. Perpeptide-substituted 12 (12)-closomers incorporating cytoplasmic translocation signals and nuclear translocation signals as new intracellular vehicles can be synthesized; 7. Polyamino-substituted 12 (12)-closomers as transfection reagents for the delivery of antisense oligonucleotides can be formed; 8. 12 (12)-closomers substituted with carborane or polyborane derivatives as new boron- rich macromolecules for the boron neutron capture therapy of cancer (BNCT) can be formed; 9. Micellar aggregates containing spherical closomeric cores for the encapsulation of biologically active substrates and drugs can be formed; and 10. Polymers based on closomers or the preparation of polymers with closomers as additives can be synthesized.

The closomers can also find applications in the fields of host-guest chemistry, catalysis and material science, amongst others.