Polymeric Organosilicon Systems. 30. Preparation and Properties of Polymers Containing Iron(0)-Complex-Coordinated Silole Units

UV irradiation of poly[(tetraethyldisilanylene)(3,4-diethynylenesilole)] in the presence of an excess of Fe(CO) 5 led to the formation of Fe(CO) 3 -coordinated silole units in the polymer backbone. The ratio of the Fe(CO) 3 -coordinated and noncoordinated units in the resulting polymer was determined to be 2:1 by 1 H NMR spectrometry. Similar treatment of poly[(tetramethyldisilanylene)(3,4-diethynylenesilole)] also afforded the corresponding Fe(CO) 3 -coordinated polymer. The polymers with Fe(CO) 3 -coordinated silole units exhibit slightly red-shifted UV absorption bands, relative to the parent noncoordinated polymers. When doped with FeCl 3 vapor, the Fe(CO) 3 -coordinated polymers became semiconducting with conductivities on the order of 10 - 5 S/cm, much higher than the conductivities of the parent polymers doped with FeCl 3, which were determined to be less than 10 - 8 S/cm. Crystal structures of two model compounds having Fe(CO) 3 -coordinated or noncoordinated 3,4-diethynylenesilole units were determined by X-ray crystallography, which suggest enhanced π-conjugation in the Fe(CO) 3 -coordinated 3,4-diethynylenesilole ring as compared with the noncoordinated one.