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 H-1 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 FeCl3 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 FeCl3, 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 pi-conjugation in the Fe(CO)(3)-coordinated 3,4-diethynylenesilole ring as compared with the noncoordinated one.