Highly polarized ruthenium alkynyls with nitrothienyl substituents

Abstract

Me 3SiCCC 4H 2S-5-NO 2 was synthesized in good yield by palladium-catalyzed cross-coupling of ethynyltrimethylsilane and 2-bromo-5-nitrothiophene or 2-iodo-5-nitrothiophene. Reactions of Me 3SiCC(C 4H 2S)NO 2 with a series of ruthenium chloride complexes [RuClLL′(Cp′)] gave the alkynyls [Ru(2-CCC 4H 2S-5-NO 2)LL′(Cp′)] (L, L′=CO, PMe 2Ph or PPh 3; Cp′=C 5H 5 or C 5Me 5). These metal complexes, each with a strongly electron-donating metal center at one end and an electron-accepting organic substituent at the other end of a π-conjugated chain, are strongly polarized and are expected to demonstrate non-linear optical activity.