Synthesis and properties of polyacetylenes having pendant carbazole groups

Five novel carbazole-containing polymers, i.e., poly(3,6-di-tert-butyl-9-prop-2-ynylcarbazole) [poly(t-Bu(2)CzPr)], poly(9-but-2-ynylcarbazole) [poly(CzBu)], poly(3,6-di-tert-butyl-9-but-2-ynylcarbazole) [poly(t-Bu(2)CzBu)], poly(9-(4-ethynylphenyl)carbazole) [poly(p-CzPA)], and poly(9-(4-prop-1-ynylphenyl)carbazole) [poly(p-CzPPr)] were synthesized by the polymerization of the corresponding carbazole-containing acetylene monomers using [(norbornadiene)RhCl](2)-Et3N, WCl6, MoCl5, TaCl5, and NbCl5 in conjunction with Sn, Bi, Sb, and Si cocatalysts and W(CO)(6)-hv/CCl4 catalysts. The UV-vis absorption band edge wavelengths of poly(t-Bu(2)CzPr) and poly(p-CzPA) were longer than those of the corresponding polymers substituted by methyl group at the main chain, poly(t-Bu(2)CzBu) and poly(p-CzPPr), respectively. The band edge wavelengths of phenylene-spacer-containing polymers, poly(p-CzPA) and poly(p-CzPPr), were longer than those of methylene-spacer-containing polymers, poly(t-Bu(2)CzPr) and poly(t-Bu(2)CzBu), respectively. Poly(p-CzPA) obtained by WCl6-n-Bu4Sn-catalyzed polymerization exhibited UV-vis absorption apparently at a longer wavelength than the MoCl5-n-Bu4Sn-based counterpart did. Poly(t-Bu(2)CzPr) showed photoconductivity. The temperatures for 5% weight loss of the polymers were around 300-350 degreesC under air.