Ruthenium(II) complexes with substituted 2-(methylthio)-phenylsalicylaldimine Schiff-base ligands

Three tridentate mono-anionic Schiff base ligands of the O,N,S-donor set, namely 3,5-dibromo N-(2-(methyl-sulfanyl)phenyl)salicylaldimine (HL1), 5-chloro-N-(2-(methyl-sulfanyl)phenyl)salicylaldimine (HL2), and 3,5-di tert butyl N-(2-(methylsulfanyl)phenyl)-salicylaldimine (HL3) were prepared. Reaction of [Ru(PPh3)(3)Cl-2] and equal equiv. of HL1 in tetrahydrofuran in the presence of triethylamine afforded complex [Ru(L1)(PPh3)(2)Cl] (1) with two triphenylphosphine ligands trans to each other. Treatment of HL2 with equal equiv. of [RuHCl(CO) (PPh3)(3)], [Ru(CO)(2)Cl-2](n) or cis- [RuCl2(DMSO)(4)] (DMSO = dimethylsulfoxide) gave complexes [Ru(L2)(CO) (PPh3)Cl] (2), [Ru(L2)(CO)(2)C1] (3), and [Ru(L2)(DMSO)(2)Cl] (4), respectively. Interactions between HL3 and [Ru(CO)(2)Cl-2](n), [Ru(COD)Cl-2](2) (COD = 1,5-cyclooctadiene), or RuCl3 center dot 3H(2)O resulted in isolation of ruthenium (II) complexes [Ru(L3)(CO)(2)Cl] (5), [Ru(L3)(COD)Cl] (6), and [Ru(L3)(2)] (7), respectively. The structures of complexes 1-7 have been unambiguously established by single-crystal X-ray crystallography. The electrochemical properties of complexes 1-7 were also investigated.