Syntheses, structures and catalytic properties of new mononuclear terpyridine-manganese(II) complexes with tetraphenylimido-diphosphinate and diphenylphosphinate ligands

Abstract

Treatment of manganese(II) acetate tetrahydrate [Mn(CH3COO)2·4H2O] with one equivalent of 2,2′:6′,2′′-terpyridine (terpy) and two equivalents of potassium tetraphenylimido-diphosphinate K[N(Ph2PO)2] in methanol afforded a mononuclear manganese(II) complex, [(terpy)Mn{η1-O-N(Ph2PO)2}2(H2O)] (1), with two terminal [N(Ph2PO)2]– ligands. Interaction of [Mn(CH3COO)2·4H2O] with one equivalent of terpy in the presence of both K[N(Ph2PO)2] and Ph2PO2K in methanol gave a mononuclear manganese(II) complex [(terpy)Mn(η1-O-O2PPh2){N(Ph2PO)2}] (2) with a chelated [N(Ph2PO)2]– ligand. Treatment of manganese(II) dichloride tetrahydrate [MnCl2·4H2O] with three equivalents of K[N(Ph2PO)2] in methanol resulted in isolation of a mononuclear manganese(III) complex [Mn{η1-O-N(Ph2PO)2}-{N(Ph2PO)2}2] (3) with one terminal and two chelated [N(Ph2PO)2]– ligands. Reaction of [Mn(CH3COO)2·4H2O] with one equivalent of 4′-phenyl-[2,2′:6′,2′′]-terpyridine (4-Ph-terpy) and two equivalents of Ph2PO2K in methanol gave [(4-Ph-terpy)Mn(η1-O-O2PPh2)2(H2O)] (4) with a labile water molecule. Complexes 1–4 have been spectroscopically characterized and their structures have been established by single-crystal X-ray diffraction. Catalytic behavior of 1 and 4 for sulfide oxidation was also investigated.