Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite, bis(2-diphenylphosphinoxynaphthalen-1-yl)methane: application of Ru(II) complexes towards the hydrogenation of styrene and phenylacetylene

Abstract

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite Ph2P{(-OC10H6)(μ-CH2)(C10H6O-)}PPh2 (1) are described. Reactions of bisphosphinite 1 with [Ru(η6-p-cymene)(μ-Cl)Cl]2 and RuCl2(PPh3)3 afford mono- and bis-chelate complexes [RuCl(η6-p-cymene){η2-Ph2P{(-OC10H6)(μ-CH2)(C10H6O-)}PPh2-κP,κP}]Cl (2) and trans-[RuCl2{η2-Ph2P{(-OC10H6)(μ-CH2)(C10H6O-)}PPh2-κP,κP}2] (3), respectively. Treatment of 1 with CuX (X = Cl, Br and I) furnish 10-membered chelate complexes of the type [Cu(X){η2-Ph2P(-OC10H6)(μ-CH2)(C10H6O-)PPh2-κP,κP}] (4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN)4]PF6 affords a bis-chelated cationic complex [Cu{η2-Ph2P(-OC10H6)(μ-CH2)(C10H6O-)PPh2-κP,κP}2][PF6] (7). Reaction between 1 and AgOTf produce both mono- and bis-chelated complexes [Ag{η2-Ph2P(-OC10H6)(μ-CH2)(C10H6O-)PPh2-κP,κP}(SO3CF3)] (8) and [Ag{η2-Ph2P(-OC10H6)(μ-CH2)(C10H6O-)PPh2-κP,κP}2][SO3CF3] (9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh3] affords chelate complex of the type [Ag{η2-Ph2P(-OC10H6)(μ-CH2)(C10H6O-)PPh2-κP,κP}(PPh3)(SO3CF3)] (10). All the complexes were characterized by 1H NMR, 31P NMR, elemental analysis and mass spectrometry, including low-temperature NMR studies in the case of silver complexes. The molecular structures of 4 and 6 are determined by X-ray diffraction studies. Ruthenium complexes 2 and 3 promote catalytic hydrogenation of styrene and phenylacetylene with good turnover numbers.