No abstract

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

Pd(II)-catalyzed insertion reactions of phenyl-and diphenylacetylene, 1-hexyne, and 1,4-diphenylbutadiyne into the Si-Si bond of the 4,5,10-trisilabicyclo[6.3.0]undeca-1(11),8-diene-2,6-diyne 1a gave the 4,7,12-trisilabicyclo[8.3.0]trideca-1(13),5,10-triene-2,8-diynes 3-6. With 1,4-bis(trimethylsilyl)butadiyne, 1,4-bis-silylation of the butadiyne occurred specifically to afford the 4,9,14-trisilabicyclo[10.3.0]pentadeca-1(15),5,6,7,12-pentaene-2,10-diyne 7.