Siloles, or silacyclopentadienes, have unique electronic properties due to interaction between the butadiene π* orbital and the silylene σ* orbital. Consequently they have drawn interest for use in a variety of organic electronic interactions. A silylene bridged viologen has been synthesized for use in electrochromic applications. Lithiation of 3,3’-dibromo-4,4’-bipyridine and subsequent reaction with dichlorodimethylsilane leads to the corresponding dipyridinosilole. The dipyridinosilole can be converted to the methyl viologen analogue by reaction with methyl triflate. It is stable and can be isolated but hydrolyses upon exposure to air. Its electrochemical, spectroelectrochemical, and spectroscopic properties have been investigated.Similar chemistry was exploited to synthesize spiro-linked siloles for use in electronic applications. Lithiation of dibromo-2,2’-diiodibiphenyls followed by reaction with SiCl4 leads to the corresponding tetrabromospirosilabifluorenes. The tetrabromospirosilabifluorenes were explored for their suitability toward Buchwald-Hartwig amination and Suzuki coupling, but the spiro linkage was found to cleave under basic conditions.
