The U. S. Government has certain rights in this invention pursuant to Grant No. CHE 963611 awarded by the National Science Foundation.

BACKGROUND Prior art laser dyes primarily consist of coumarin and rhodamine compositions. However, these dyes along with other commercially available materials have inherent limitations as dye lasers, including moderate energies and relatively high degrees of photodecomposition. Recently, promising experimental results have been described for the use of pyrromethene-BF2 compositions as laser dyes. However, in order to maximize the commercial potential of pyrromethene-BF2 compositions a compatible solid-state matrix with good mechanical properties is required.

SUMMARY The present invention relates to modified pyrromethene-BF2 complexes that may be co- polymerized with a cyclic olefin (or a combination of cyclic olefin) via ring-opening metathesis polymerization ("ROMP") reactions or addition polymerization. In general, the pyrromethene-BF2 complexes of the present invention include at least one cycloalkenyl substituent. In preferred embodiments, the cycloalkenyl substituent is a norbornenyl or a norbornenyl derivative. In another aspect of the present invention, ROMP or addition derived polymers with pyrromethene-BF2 complexes dispersed therein are disclosed. These inventive pyrromethene-BF2-containing ROMP or addition polymers are solid state lasers and may be used for a variety of basic research, medical and military applications.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to modified pyrromethene-BF2 complexes that may be co- polymerized with a cyclic olefin (or a combination of cyclic olefins) via ring-opening metathesis polymerization ("ROMP") reactions or addition polymerization. In general, the inventive pyrromethene-BF2 complexes are of the general formula wherein R', R2, R3, R4, R5, R6, and R7 are each independently hydrogen, cyano, or a substituent selected from the group consisting of C,-C20 alkyl (primary, secondary, or tertiary), cycloalkyl, C2-C20 alkenyl, cycloalkenyl, aryl, and heteroaryl, each substituent optionally substituted with one or more moieties selected from Cl-C5 alkyl, aryl, or a functional group selected from the group consisting of alcohol, sulfonic acid, phosphine, phosphonate, phosphonic acid, thiol, ketone, aldehyde, ester, ether, amine, quaternary ammonium, imine, amide, imide, imido, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, acetal, ketal, boronate, cyanohydrin, hydrazone, oxime, oxazole, oxazoline, oxalane, hydrazide, enamine, sulfone, sulfide, sulfenyl, and halogen, provided that at least one of Rl, R2, R3, R4, R5, R6, and R7 includes a cycloalkenyl moiety.

In preferred embodiments, R', R, R3, R4, R5, and R6 are each methyl, ethyl, propyl, isopropyl, phenyl, or cyano and R inclues a cycloalkenyl moiety. The cycloalkenyl moiety may be monocyclic or polycyclic and may optionally include heteroatoms and functional groups. Suitable examples of cycloalkenyl moieties include but are not limited to norbornenyl, norbornadienyl, dicyclopentadienyl, tricyclopentadienyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cycloheptenyl, cyclooctenyl, cyclooctadienyl, cyclododecenyl, 7-oxanorbornenyl, 7-oxanorbornadienyl tetracyclododecadienyl,

tetracyclododecenyl, and derivatives therefrom. In more preferred embodiments, R', R2, R3, R4, R5, and R6 are each methyl or ethyl and R inclues a cycloalkenyl that is a norbornenyl or its derivative. In the case of addition polymerization the cycloalkenyl moiety is limited to a cycloalkenyl that is a norbornenyl or its derivatives.

A particularly preferred embodiment of the present invention is complex 1: In another aspect of the present invention, an inventive pyrromethene-BF2 complex (or a combination of pyrromethene-BF2 complexes) may be co-polymerized with a cyclic olefin (or a combination of cyclic olefins) in the presence of a metathesis or addition catalyst to form a ROMP-or addition-derived polymer product. These pyrromethene-BF2 complex-ROMP polymers may be used as solid-state laser-dye materials and offer advantages over nonlinear techniques (e. g. Raman scattering and optical parametric oscillation) such as virtually thresholdless operation, relative insensitivity to fluctuations in pump laser intensity, continuous tunability over the gain region, the lack of a need for the excitation source to be coherent, and a low chemical hazard. Moreover, these inventive polymers can be easily molded or shaped to fit specific applications or devices.

Applications include medical uses such as surgical tools and for photodynamic therapy, and military uses such as underwater communication and night-vision devices.

The cyclic olefins used in the ROMP reaction may be monocyclic or polycyclic, may optionally include heteroatoms, and may include one or more functional groups. Suitable cyclic olefins include but are not limited to norbornene, norbornadiene,

dicyclopentadiene, tricyclopentadiene, tetracyclododecene, tetradodecadiene, cyclopropene, cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, methylnorbornene, ethylnorbornene, butylnorbornene, hexylnorbornene, decylnorbornene, methyltetracyclododecene, 7-oxanorbornene, 7-oxanorbornadiene, and derivatives therefrom. Illustrative examples of suitable functional groups include but are not limited to hydroxyl, thiol, ketone, aldehyde, ester, ether, amine, imine. amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and halogen.

Preferred cyclic olefins include norbornene and dicyclopentadiene and their respective homologs and derivatives. The use of dicyclopentadiene for ROMP polymerization is particularly preferred.

The cyclic olefins used in the addition polymerization reaction are selected from polycyclic olefins based on a norbornene structure and its homologs and derivatives. The polycyclic olefins optionally include heteroatoms, and may include one or more functional groups. Suitable cyclic olefins include but are not limited to norbornene, norbornadiene, dicyclopentadiene, tricyclopentadiene, tetracyclododecene, tetradodecadiene, cyclopropene, cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, methylnorbornene, ethylnorbornene, butylnorbornene, hexylnorbornene, decylnorbornene, methyltetracyclododecene, 7-oxanorbornene, 7- oxanorbornadiene, and derivatives therefrom. Illustrative examples of suitable functional groups include but are not limited to hydroxyl, thiol, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and halogen. Preferred cyclic olefins include norbornene and dicyclopentadiene and their respective homologs and derivatives. The use of norbornene, methylnorbornene, butylnorbornene, and hexylnorbornene for addition polymerization is particularly preferred.

Any metathesis catalyst may be used. However, because of the incredible versatility and functional group tolerance, ruthenium metathesis catalysts, particularly those described, for example, by U. S. Patent Nos. and 5,917,071 (which are all incorporated herein by reference) are preferred. Briefly, the ruthenium and osmium carbene catalysts possess metal centers that are formally in the +2 oxidation state, have an electron count of 16, are penta-coordinated, and are of the general formula

wherein: M is ruthenium or osmium; X and Xl are each independently any anionic ligand; L and L'are each independently any neutral electron donor ligand; R and Rl are each independently hydrogen or a substituent selected from the group consisting of C,-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C-C20 carboxylate, Ci- C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C- C20 alkylthio, Cl-C20 alkylsulfonyl and Cl-C20 alkylsulfinyl. Optionally, each of the R or R'substituent group may be substituted with one or more moieties selected from the group consisting of Cl-Clo alkyl, Cl-Cl0 alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from a halogen, a Cl-C5 alkyl, Cl-ces alkoxy, and phenyl. Moreover, any of the catalyst ligands may further include one or more functional groups. Examples of suitable functional groups include but are not limited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.

In preferred embodiments of these catalysts, the R substituent is hydrogen and the R' substituent is selected from the group consisting C1-C20 alkyl, C2-C20 alkenyl, and aryl.

In even more preferred embodiments, the R'substituent is phenyl or vinyl, optionally substituted with one or more moieties selected from the group consisting of C,-Cs alkyl, Cl-ces alkoxy, phenyl, and a functional group. In especially preferred embodiments, Rl is phenyl or vinyl substituted with one or more moieties selected from the group consisting of chloride, bromide, iodide, fluoride,-N02,-NMe2, methyl, methoxy and phenyl. In the most preferred embodiments, the R'substituent is phenyl or-C=C (CH3) 2.

In preferred embodiments of these catalysts, X and Xl are each independently hydrogen, halide, or one of the following groups: Cl-C20 alkyl, aryl, Cl-C20 alkoxide, aryloxide, C3- C20 alkyldiketonate, aryldiketonate, Cl-C20 carboxylate, arylsulfonate, Cl-C20 alkylsulfonate, C-C20 alkylthio, Cl-C20 alkylsulfonyl, or Cl-C20 alkylsulfinyl.

Optionally, X and Xl may be substituted with one or more moieties selected from the group consisting of Cl-Clo alkyl, Cl-Clo alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from halogen, Ci-Cs alkyi, Ci-Cs alkoxy, and phenyl. In more preferred embodiments, X and X'are halide, benzoate, Cl- C5 carboxylate, Cl-Cs alkyl, phenoxy, Cl-C5 alkoxy, Cl-Cs alkylthio, aryl, and Cl-Cs alkyl sulfone. In even more preferred embodiments, X and Xl are each halide, CF3CO2, CH3CO2, CFH2CO2, (CH3) 3CO, (CF3) 2 (CH3) CO, (CF3) (CH3) 2CO, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethanesulfonate. In the most preferred embodiments, X and X'are each chloride.

In preferred embodiments of these catalysts, L and L'are each independently selected from the group consisting of phosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine, stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, and thioether. In more preferred embodiments, L and L'are each a phosphine of the formula PR3R4R5, where R3, R4, and Rs are each independently aryl or Cl-Clo alkyl, particularly primary alkyl, secondary alkyl or cycloalkyl. In even more preferred embodiments, L and Ll ligands are each selected from the group consisting of- P (cyclohexyl) 3,-P (cyclopentyl) 3,-P (isopropyl) 3, and-P (phenyl) 3. In the most preferred embodiments, L is P (Cy) 3 and Ll is an unsubstituted or substituted imidazolidine.

Preferred examples of a catalyst with this ligand include complexes of the formula:

wherein Ar is a substituted or unsubstituted aryl or alkyl group. The aryl group may be substituted with a moiety selected from the group consisting of Cl-C20 alkyl, such as methyl, ethyl, isopropyl, etc. Preferred examples of these Ar groups include adamantyl and cyclohexyl. Even more preferred examples include mesityl or 2,6 dialkylphenyl.

These catalysts are preferred in the polymerization reaction for their reduced catalyst loading time. Using these catalysts, the catalyst loading time can be reduced to 1: 25,000 (catalyst to monomer) and eliminates the coloration brought to the polymer by the catalyst. The parts can be made colorless and thus reduces interference in the lasing experiments and results in increasing lasing efficiencies. These catalysts are described in PCT Application No. WO 00/15339 entitled Catalyst Complex with Carbene Ligand, filed September 9,1999, the contents of which are herein incorporated by reference.

In the case of addition polymerization, preferred transition metal derivatives are described, for example, by WO 00/20472, WO 00/34344, U. S. Patent Nos. 5,569,730 and 5,705.503 (the contents of each of which are herein incorporated by reference).

The ROMP or addition polymerization may occur either in the presence or absence of solvent and may optionally include formulation auxiliaries. Known auxiliaries include antistatics, antioxidants (primary antioxidants, secondary antioxidants, or mixtures thereof), light stabilizers, plasticizers, dyes, pigments, fillers, reinforcing fibers, lubricants, adhesion promoters, viscosity-increasing agents and demolding enhancers.

Illustrative examples of fillers for improving the optical physical, mechanical and

electrical properties include glass and quartz in the form of powders, beads and fibers, metal and semi-metal oxides (i. e., barium titanate), carbonates (i. e., MgCO3, CaCO3), dolomite, metal sulfates (such as gypsum and barite), natural and synthetic silicates (i. e., zeolites, wollastonite, feldspars), carbon fibers, and plastics fibers or powders. In addition, formulation auxiliaries include materials that modulate the activity of the catalyst (e. g. to either retard the activity or enhance the activity).

1,5,7,8-tetramethyl-2,6-diethyl-3-hydroxymethyl-pyrrometh ene-BF2 complex 2 has been recently identified as a useful precursor for the synthesis of monomeric units for co- polymerization.

For example, complex 2 has been used to make a methacrylate derivative that has been co-polymerized with methacrylate to form a covalently bound polymethacrylate dye matrix. Typically, the resulting methacrylate polymer contained about one dye monomer per about 1600 monomer residues with about 75%-90% incorporation. The fluorescent and absorption properties of the solid-state material were similar to an ethanol solution of the pyrromethene-BF2 complex.

Scheme 1 illustrates the synthetic strategy employed in the preparation of pyrromethene- BF2 complexes of the present invention. The basic dye unit, 5,7,8 pentamethylpyrromethene-BF2 complex was prepared according to the procedure developed by Boyer et al. (U. S. Patent No. 4,916,711 and Appl. Opt. 29: 3885 (1990), both of which are incorporated herein in their entireties).

SCHEME 1 a H3(~ Fi3 CH2C 1 {9t %) Fl HCI Fi3 H'HCI H, 40 *C H ? )X=5t 7nm ,...,/ 1)E13N. loluene 2)BFstE12O r 546 nm (. ty6%)3 J !e, s = 5 ? fl ttm =083

Scheme 2 shows the oxidation of complex 3 with DDQ to make aldehyde 4 in about 93% yield and its subsequent hydrogenation over 5% palladium on carbon to result in alcohol 2 in about 35% yield.

SCHEME 2

As illustrated by Scheme 3, the synthesis of 3- (bicyclo [2.2.1] hept-5-en-2- 7,8-tetramethylpyrromethene-BF2 complex 1 was prepared from the reaction of complex 2 with 5-norbornene-2-carbonyl chloride in dichloromethane and pyridine.

SCHEME 3 H3 Ha s HsS Hs X rMa w C2H<Hs Av C2 < Hs t-b20H pyridine H3 9) 2 1 a'H DCPD ; C2H>Hs ClHadF:" RU PCp3 iy-DCPD

The product yield was about 20% after purification by column chromatography.

Complex 1 was then co-polymerized with dicyclopentadiene ("DCPD") via ROMP using a ruthenium metathesis catalyst in a glass vial. The concentration of the dye monomer to dicyclopentadiene was 0.3 mmol/mol DCPD. However, this monomer/DCPD ratio can be reduced further by use of the RuIMes and RuSIMes catalysts. The resulting polymer product was an orange/green transparent solid material that fluoresced bright orange when irradiated under a UV light.

For the purposes of clarity, the specific details of the present invention will be illustrated with reference to especially preferred embodiments. However, it should be appreciated that these embodiments and examples are for the purposes of illustration only and are not intended to limit the scope of the present invention.

EXPERMENTAL SECTION 4 4'-dimethyl-3. 3 \5. 5', 6-pentamethylpvrromethene hydrochloride.

Acetyl chloride (7.44 g, 94.7 mmol) was added dropwise over a period of 15 minutes to a solution of 2,4-dimethyl-3-ethylpyrrole (5.00 g, 40.6 mmol) in 25 mL of dry

dichloromethane. The reaction mixture was heated at 40 °C for 1 hour, cooled to room temperature, and diluted with 290 mL of petroleum ether. The solution was triturated for 12 hours in order to cause the product to precipitate as a crystalline, red-brown solid (5.64g, 91%), mp 175-176 °C, (mp 185-186 °C, see e. g., Chen, J. H. Boyer, and M. L.

Trudell, Heteroatom Chemistry, 8: 51-54 (1997)).

296-diethyl-13*5n78-pentamethYlpYrromethene-BF Complex (3).

Triethylamine (7.75 g, 76.7 mmol) was added at room temperature to 4,4'-dimethyl- 3,3', 5,5', 6-pentamethylpyrromethene hydrochloride (5.11 g, 16.3 mmol) in 500 mL of dry toluene. The mixture was stirred for 15 minutes. Boron trifluoride etherate (13.6 mL, 111 mmol) was added dropwise with stirring. The solution became a dark fluorescent green color. The reaction mixture was heated at 80 °C for 15 min, and then cooled to 40 °C. The reaction mixture was washed with warm water (3X 100 mL) and dried over magnesium sulfate. The solvent was removed under reduced pressure, giving a dark brown solid. The crude compound was purified by silica gel column chromatography to give 3 as an orange solid, (2.65 g, 55%), mp 210-212 °C, (mp 207-208 °C, see e. g., Chen, J. H. Boyer, and M. L. Trudell, Heteroatom Chemistry, 8: 51-54 (1997)).

296-diethyl-3-formyl-15*7*8-tetramethYlpyrromethene-BF) complex (4 !.

Over a 2 hour period, ("DDQ"), (1.82 g, 8.0 mmol) in 16 mL of tetrahydrofuran ("THF") was added at 0 °C to a solution of 3 (0.64 g, 2.0 mmol) in 100 mL of aqueous THF (99%). After the DDQ/THF solution was added, the solution was stored at 0 °C for 4 hours and stirred at room temperature for 24 hours.

Upon removing the solvent under reduced pressure, a purplish residue was obtained. The residue was extracted with dichloromethane, producing a mauve colored solid. The solid was filtered and rinsed with dichloromethane (3X 50 mL). The solvent was removed under reduced pressure which produced a purplish residue, which was then purified by silica gel chromatography. A solvent system consisting of toluene/hexane (9: 1) was used to elute until a purplish oil was completely eluted; then dichloromethane/ethyl acetate (9: 1) was used for the duration of the chromatography. This gave 4 as an orange solid

(0.607 g, 91%), mp 198-199 °C, (mp 196-197 °C, see e. g., Sathyamorthi, L. T. Wolford, A. M. Haag, and J. H. Boyer, Heteroatom Chemistry, 5: 245-249 (1994)).

2, 6-diethyl-3-hydroxymethyl-1, 5, 7, 8-tetramethylpyrromethene-BF7 complex (2).

Aldehyde 4 (0.509 g, 1.63 mmol) was dissolved in hot anhydrous ethanol (200 mL) and hydrogenated over 5% palladium on carbon (0.29 g) for between about 1 and about 1.25 hours. A red-brown solid was obtained and purified by silica gel chromatography with a solvent system of dichloromethane/ethyl acetate (9: 1). Three products were obtained.

The first product to elute was 3 (0.16 g, 4%) as an orange crystalline solid; the second product to elute was starting material 4 (0.229 g, 45%); and the final product was the desired product 2 (0.178 g, 35%), also as an orange crystalline solid, mp 181-182 °C (mp 182-183 °C, see e. g., Sathyamorthi, L. T. Wolford, A. M. Haag, and J. H. Boyer, Heteroatom Chemistry, 5: 245-249 (1994)).

3- (bicvclof 2.2.l1heDt-5-en-2-carbonvloxymethvl)-2, 6-diethvl-l. 5. 7. 8- tetramethylpyrromethene-BF2 complex (1).

Freshly distilled bicyclo [2.2.1] hept-5-en-2-carbonyl chloride (1.00 g, 6.39mmol) was added dropwise to a mixture of 2 (0.115 g, 0.347 mmol) in 0.800 mL of pyridine.

Alcohol 2 did not completely dissolve in the pyridine before adding distilled bicyclo [2.2.1] hept-5-en-2-carbonyl chloride. The solution was allowed to stir for 5 minutes, water (10 mL) was added while stirring vigorously, and the solution was cooled in an ice bath for 10 minutes. The water was removed and the remaining oil was washed with 5% sodium carbonate (5 mL). The solution was stirred until no more gas was evolved. The aqueous layer was removed and the oil was purified on a column of silica gel with dichloromethane to yield product 1 as an orange crystalline solid (0.023 g, 8%); 'H-NMR (deuteriochloroform) 6.13 (m, lH), 5.30 (d, 1H), 4.75 (s, 2H), 3.65 (s, 1H) 3.25 (m, lH), 2.65 (s, 3H), 2.53 (s, 3H), 2.42 (m, 4H) 2.3 (s, 6H) 1.91 (m, 1H), 1.38 (m, 2H), 1.25 (s, 2H), 1.10 (m, 6H).

(2, 6-diethvl-1 , 5 7 8-pentamethvlpvrromethene-BF complex)-dicyclopentadiene co- Polymer.

Dicyclopentadiene ("DCPD") (13.3 mL, 0.103 mol) was pipetted into 250 mL flask. The flask was heated at 40 °C to keep the DCPD from solidifying. The ruthenium catalyst (Cl) 2 (PCy3) 2Ru=CHC=C (CH3) 2 (10 mg, 0.013 mmol) was dissolved in approximately 1.0 mL of dichloromethane. The monomer 1 (1.0 mg, 0.0022 mmol) was added to the DCPD solution. The catalyst solution was pipetted into the flask to initiate the ROMP process.

After a few minutes the orange solution began to thicken. The viscous liquid was transferred to a mold (glass scintillation vial). The mold containing the polymer was placed in a 40 °C oil bath until completely solidified. The mold was placed into an oven and heated at 100 °C overnight. The polymer was then allowed to cool and then removed from the mold to give a cylindrical solid that was orange and transparent. The sample was cut and polished into a disk. Disk thickness 1.0 mm; Fluorescence , max 555 nm.

2 6-diethyl-1, 3, 5, 7, 8-pentamethylpyrromethene-BFZ complex doped dicyclopentadiene polymer.

Dicyclopentadiene ("DCPD") (13.3 mL, 0.103 mol) was pipetted into 250 mL flask. The flask was heated at 40 °C to keep the DCPD from solidifying. The ruthenium catalyst, (Cl) 2 (PCy3) 2Ru=CHC=C (CH3) 2, (10 mg, 0.013 mmol) was dissolved in approximately 1.0 mL of dichloromethane. The dye compound 3 (1.0 mg, 0.0022 mmol) was added to the DCPD solution. The catalyst solution was pipetted into the flask to initiate the ROMP process. After a few minutes the orange solution began to thicken. The viscous liquid was transferred to a mold (glass scintillation vial). The mold containing the polymer was placed in a 40 °C oil bath until completely solidified. The mold was placed into an oven and heated at 100 °C overnight. The polymer was then allowed to cool and then removed from the mold to give a cylindrical solid that was orange and transparent: The sample was cut and polished into a disk. Disk thickness 1.1 mm; Absorption Bma 526 nm; Fluorescence BmaX 549 nm; Laser Bma 565 nm 34.4% efficiency.