Synthesis, crystal structure and spectroscopic characterization of new neutral and cationic (η6-p-cymene)–ruthenium(II) complexes with phosphine–amide ligands

Abstract

The dimeric starting material [Ru(η6-p-cymene)(μ-Cl)Cl]2 reacts with the phosphino-amides o-Ph2P–C6H4CO–NH–R [R=iPr (a), Ph (b), 4-MeC6H4 (c), 4-FC6H4 (d)] to give the mononuclear compounds 1a–d [RuCl(η6-p-cymene)(o-Ph2P–C6H4–CO–NH–R)]Cl. The subsequent reaction of these complexes with KPF6 produced the cationic species 2a–d [RuCl(η6-p-cymene)(o-Ph2P–C6H4–CO–NH–R)][PF6] in which phosphino-amides also act as rigid P,O-chelating ligands. The molecular structures of 2b–d were determined crystallographically. Amide deprotonation is achieved when complexes 2a–d were made react with 1M aqueous solution of KOH, affording the corresponding neutral species 3a–d [RuCl(η6-p-cymene)(o-Ph2P–C6H4–CO–N–R)] in which a P,N-coordination mode is suggested.