Search

Benzoic acid (4-(2-propoxy)-3-vinylphenyl) ester (1), the divinyl compounds terephthalic acid bis(4-(2-propoxy)-3-vinylphenyl) ester (2) and bis(4-(2-propoxy)-3-vinylphenoxy)diphenylsilane (3), and the trivinyl compound benzene-1,3,5-tricarboxylic acid tris(4-(2-propoxy)-3-vinylphenyl) ester (4) were used for the synthesis of a series of ruthenium-based mono-, bi-, and trinuclear metathesis catalysts, i.e., RuX2(IMesH2)(CH-2-(2-PrO)-C6H3-5-OOCC6H5) (X Cl, I1a; X OOCCF3, I1b), 1,4-RuX2(IMesH2)(CH-2-(2-PrO)-C6H3-5-OOC)2C6H4(X Cl, I2a; X OOCCF3, I2b), RuX2(IMesH2)(CH-2-(2-PrO)-C6H3-5-O)2SiPh2(X Cl, I3a; X OOCCF3, I3b), and 1,3,5-RuX2(IMesH2)(CH-2-(2-PrO)-C6H3-5-OOC)3C6H3(X Cl, I4a; X OOCCF3, I4b) (IMesH2 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene), where the corresponding trifluoroacetate-derived systems were prepared from the parent dichloro-substituted initiators via reaction with CF3COOAg. Initiators I1a−I4aand I1b−I4bwere used for the cyclopolymerization of a series of 1,6-heptadiynes, i.e., dimethyl dipropargylmalonate (M1), diethyl dipropargylmalonate (M2), di-tert-butyl dipropargylmalonate (M3), 4-(ethoxycarbonyl)-1,6-heptadiyne (M4), 4,4-(bishydroxymethyl)-1,6-heptadiyne (M5), and 4-(hydroxymethyl)-1,6-heptadiyne (M6), to yield the corresponding An−X−Antype block and (An)3X type tristar copolymers. Cleavage of the An−X−Antype block copolymer M225−CH-2-(2-PrO)-1,5-C6H3-O-SiPh2-O-2-(2-PrO)-1,5-C6H3-CH-M225with tetrabutylammonium fluoride resulted in the formation of the low-PDI telechelic homopolymer M225-CH-2-(2-PrO)-1,5-C6H3-OH with half the molecular weight of the parent block copolymer, indicative for an equal activity of both initiator sites in I3b. An interesting finding was the fact that monomers with reduced steric demands in the 4-position (M1, M4, M5, and M6) could even be polymerized with chlorine-based initiators; however, values for Mnwere in general lower than the calculated ones. In contrast to Mo-based initiators, no influence of monomer size on the structure of the final polymer in terms of the ratio of 1,2-(cyclopent-1-ene)vinylene and 1,3-(cyclohex-1-ene)methylidene units, respectively, was observed.

Benzoic acid (4-(2-propoxy)-3-vinylphenyl) ester (1), the divinyl compounds terephthalic acid bis(4-(2-propoxy)-3-vinylphenyl) ester (2) and bis(4-(2-propoxy)-3-vinylphenoxy)diphenylsilane (3), and the trivinyl compound benzene-1,3,5-tricarboxylic acid tris(4-(2-propoxy)-3-vinylphenyl) ester (4) were used for the synthesis of a series of ruthenium-based mono-, bi-, and trinuclear metathesis catalysts, i.e., RuX2(IMesH2)(&dbd;CH-2-(2-PrO)-C6H3-5-OOCC6H5) (X = Cl, I1a X = OOCCF3, LUC), 1,4-[RuX2(IMesH2)(&dbd;CH-2-(2-PrO)-C6H3-5-OOC)]2C6H4 (X = Cl, Ota X = OOCCF3, I2b), [RuX2(IMesH2)(&dbd;CH-2-(2-PrO)-C6H3-5-O)]2SiPh2 (X = Cl, I3a X = OOCCF3, I3b), and 1,3,5-[RuX2(IMesH2)(&dbd;CH-2-(2-PrO)-C6H3-5-OOC)]3C6H3 (X = Cl, I4a X = OOCCF3, I4b) (IMesH2 = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene), where the corresponding trifluoroacetate-derived systems were prepared from the parent dichloro-substituted initiators via reaction with CF3COOAg. Initiators I1a−I4a and LUC−I4b were used for the cyclopolymerization of a series of 1,6-heptadiynes, i.e., dimethyl dipropargylmalonate (M1), diethyl dipropargylmalonate (M2), di-tert-butyl dipropargylmalonate (M3), 4-(ethoxycarbonyl)-1,6-heptadiyne (M4), 4,4-(bishydroxymethyl)-1,6-heptadiyne (M5), and 4-(hydroxymethyl)-1,6-heptadiyne (M6), to yield the corresponding An−X−An type block and (An)3X type tristar copolymers. Cleavage of the An−X−An type block copolymer M225−CH-[2-(2-PrO)-1,5-C6H3]-O-SiPh2-O-[2-(2-PrO)-1,5-C6H3]-CH-M225 with tetrabutylammonium fluoride resulted in the formation of the low-PDI telechelic homopolymer M225-CH-[2-(2-PrO)-1,5-C6H3]-OH with half the molecular weight of the parent block copolymer, indicative for an equal activity of both initiator sites in I3b. An interesting finding was the fact that monomers with reduced steric demands in the 4-position (M1, M4, M5, and M6) could even be polymerized with chlorine-based initiators; however, values for Mn were in general lower than the calculated ones. In contrast to Mo-based initiators, no influence of monomer size on the structure of the final polymer in terms of the ratio of 1,2-(cyclopent-1-ene)vinylene and 1,3-(cyclohex-1-ene)methylidene units, respectively, was observed.

The molybdenum-based binuclear Schrock-type initiator 1,4-{Mo(N-2,6-(2-Pr)2C6H3)[OCMe(CF3)2]2CH}2C6H4 (1) was used for the ring-opening metathesis polymerization (ROMP) of norborn-2-ene (NBE) and for the cyclopolymerization of a series of 1,6-heptadiynes, i.e., dimethyl dipropargylmalonate (M1), diethyl dipropargylmalonate (M2), di-tert-butyl dipropargylmalonate (M3), 4-(ethoxycarbonyl)-1,6-heptadiyne (M4), 4,4-bis(hydroxymethyl)-1,6-heptadiyne (M5), and 4-(hydroxymethyl)-1,6-heptadiyne (M6) to form the corresponding Mn−X−Mn block copolymers. The polymerization systems M1-1 (monomer M1 polymerized by the action of initiator 1) and M2-1 fulfilled the criteria of a class IV and class V living system, respectively. Poly-M1, poly-M2, poly-M3, and poly-M4 consisted of 40%, 50%, 58%, and 32% 1,2-(cyclopent-1-ene)vinylenes and 60%, 50%, 42%, and 68% 1,3-(cyclohex-1-ene)methylidenes, respectively. Finally, the block copolymers M225-b-M125-CH-1,4-C6H4-CH-M125-b-M225, M135-b-M235-CH-1,4-C6H4-CH-M235-b-M135, M125-b-NBE35-CH-1,4-C6H4CH-NBE35-b-M125, M240-b-NBE26-CH-1,4-C6H4-CH-NBE26-b-M240, NBE50-b-M135-CH-1,4-C6H4-CH-M135-b-NBE50, and NBE30-b-M225-CH-1,4-C6H4-CH-M225-b-NBE30 were prepared. Using AFM, films of M125-CH-1,4-C6H4-CH-M125 were found to be homogeneous, while phase separation was observed for M125-b-NBE35-CH-1,4-C6H4-CH-NBE35-b-M125.