Synthesis, characterization, and X-ray structural analysis of some half-sandwich ruthenium(II) arene complexes with new N,S-donor Schiff base ligands

A series of cationic, half-sandwich ruthenium complexes with the general formula [(η6-arene)RuCl(R1S-C6H4-2-CHdouble bond; length as m-dashNR2)]+ (arene = p-cymene or hexamethylbenzene; R1 = CH2Ph, iPr, or Et; R2 = aryl) have been prepared from the reaction of [(η6-arene)RuCl2]2 with various N,S-donor Schiff base ligands derived from 2-(alkylthio)benzaldehyde and several primary amines. All of the ruthenium complexes were characterized by IR, 1H NMR, electrochemistry, and UV/Vis spectroscopies. The p-cymene complexes undergo irreversible oxidations while the hexamethylbenzene complexes undergo quasi-reversible oxidations. The molecular structures of ligand 1a and complexes 4a, 4l, and 5e were determined by X-ray crystallography.