Syntheses, Structures, and Properties of Ruthenium(II) Complexes with NOS Tridentate Schiff Base Ligands

Abstract Treatment of the Schiff base (E)‐((2‐(methylsulfinyl phenyl))imino)methyl)‐4‐nitrophenol (HL1) with [RuHCl(CO)(PPh3)3] and cis‐[RuCl2(dmso)4] (dmso = dimethyl sulfoxide) in the presence of triethylamine afforded complexes [RuCl(L1)(CO)(PPh3)] (1) and [RuCl(L1)(dmso)2] (2), respectively. Similar reactions between (E)‐4‐chloro‐2‐((2‐(methylsulfinyl phenyl)imino)methyl) phenol (HL2) and [RuCl2(PPh3)3] or [RuCl2(cod)]n (cod = 1,5‐cyclooctadiene) gave complexes [RuCl(L2)(PPh3)2] (3) and [Ru(L2)2] (4), respectively. The molecular structures of the ruthenium(II) complexes 1−4 were confirmed by single‐crystal X‐ray crystallography, showing that the ruthenium metal centers are all six‐coordinated with the tridentate [ONS] Schiff base ligands L1‐/L2‐ to form a five‐membered and a six‐membered chelate ring. The O‒Ru‒S bond angles of the chelate ligands L1‐/L2‐ in complexes 1−4 range from 172.30(14)˚ to 176.8(2)˚. Complexes 1−4 were also characterized by infrared, 1H, 13C, COSY, NOESY and HSQC NMR, UV‐vis spectroscopies and electrochemical tests. In addition, the catalytic properties of ruthenium complexes 1−4 were investigated for the cyclopropanation of styrene.