Synthesis and structural characterization of ruthenium complexes with 1-aryl-imidazole-2-thione

Abstract

Treatment of [RuCl2(PPh3)3] with 2 equiv. HimtMPh (HimtMPh = 1-(4-methyl-phenyl)-imidazole-2-thione) in the presence of MeONa afforded cis-[Ru(κ 2-S,N-imtMPh)2(PPh3)2] (1), while interaction of [RuCl2(PPh3)3] and 2 equiv. HimtMPh in tetrahydrofuran (THF) without base gave [RuCl2(κ 1-S-HimtMPh)2(PPh3)2] (2). Treatment of [RuHCl(CO)(PPh3)3] with 1 equiv. HimtMPh in THF gave [RuHCl(κ 1-S-HimtMPh)(CO)(PPh3)2] (3), whereas reaction of [RuHCl(CO)(PPh3)3] with 1 equiv. of the deprotonated [imtMPh]− or [imtNPh]− (imtNPh = 1-(4-nitro-phenyl)-2-mercaptoimidazolyl) gave [RuH(κ 2-S,N-imtRPh)(CO)(PPh3)2] (R = M 4a, R = N 4b). The ruthenium hydride complexes 4a and 4b easily convert to their corresponding ruthenium chloride complexes [RuCl(κ 2-S,N-imtMPh)(CO)(PPh3)2] (5a) and [RuCl(κ 2-S,N-imtNPh)(CO)(PPh3)2] (5b), respectively, in refluxing CHCl3 by chloride substitution of the RuH. Photolysis of 5a in CHCl3 at room temperature afforded an oxidized product [RuCl2(κ 2-S,N-imtMPh)(PPh3)2] (6). Reaction of 6 with excess [imtMPh]− afforded 1. The molecular structures of 1·EtOH, 3·C6H14, 4b·0.25CH3COCH3, and 6·2CH2Cl2 have been determined by single-crystal X-ray crystallography.