POLYMERIC ORGANOSILICON SYSTEMS .21. SYNTHESIS AND PHOTOCHEMICAL, CONDUCTING, AND THERMAL-PROPERTIES OF (2,6-2,5-DIETHYNYLENEPYRIDYLENE AND2,5-DIETHYNYLENEPYRIDYLENE)DISILANYLENE POLYMERS

The reactions of 1,2-diethyl-1,2-dimethyl-, 1,1,2,2-tetraethyl-, 1,2-d ibutyl-1,2-dimethyl-, and 1,2-dihexyl-1,2-dimethyl-1,2-diethynyldisila ne (1a-d) with 2,6-dibromopyridine were carried out in the presence of a Pd(PPh(3))(4)-CuI catalyst in refluxing triethylamine to give poly[ (2,6-diethynylenepyridylene)disilanylenes] (2a-d) with molecular weigh ts of 15 000-28 000. Similar treatments of 1a-d with 2,5-dibromopyridi ne under the same conditions afforded poly[(2,5-diethynylenepyridylene )disilanylenes] (3a-d) with molecular weights of 19 000-39 000. Irradi ation of 2a-d and 3a-d with a low-pressure mercury lamp resulted in cl eavage of the silicon-silicon bonds. When 3a-d were doped with iodine or ferric chloride vapor, polymers with conductivities of 10(-4)-10(-7 ) S.cm(-1) level were obtained. Thermal properties of these polymers w ere also examined.