Synthesis, characterization and crystal structures of ruthenium complexes with bidentate chiral salicylaldiminato ligands

Abstract

Abstract Condensations of salicylaldehyde and 4-chlorosalicylaldehyde with (R)-α-methylbenzylamine in refluxing ethanol afforded the chiral Schiff base ligands (R)-N-(1-phenylethyl)salicylidene (HL1∗) and (R)-N-(1-phenylethyl)(4-chlorosalicylidene) (HL2∗), respectively. Similarly, reaction of 3,5-di-tert-butylsalicylaldehyde and (S)-2-amino-3-methylbutan-1-ol gave the chiral Schiff base ligand (S)-N-(1-hydroxymethylisobutyl)(3,5-di-tert-butylsalicylidene) (HL3∗). Treatment of (Et4N)[RuCl4(MeCN)2] and [RuCl3(NO)(PPh3)2] with HL1∗ in the presence of triethylamine afforded an anionic ruthenium(III) complex (R,R)-(Et4N)[Ru(κ2-N,O-L1∗)2Cl2] (1) and a neutral ruthenium(II) nitrosyl complex (R)-[Ru(κ2-N,O-L1∗)(NO)Cl2(PPh3)] (2), respectively. Interaction of [RuCl2(PPh3)3] and 2 equiv. HL2∗ led to isolation of a ruthenium(III) complex (R,R)-[Ru(κ2-N,O-L2∗)2Cl(PPh3)] (3). Reaction of [Ru(NO)Cl3·xH2O] and HL3∗ gave an anionic ruthenium(II) nitrosyl complex (S)-(Et3NH)[Ru(κ2-N,O-L3∗)(NO)Cl3] (4). The molecular structures of ligands HL1∗, HL2∗ and ruthenium complexes 1–4 have been determined by single-crystal X-ray crystallography.