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 Ph 2P{(-OC 10H 6)(μ-CH 2)(C 10H 6O-)}PPh 2 ( 1) are described. Reactions of bisphosphinite 1 with [Ru(η 6- p-cymene)(μ-Cl)Cl] 2 and RuCl 2(PPh 3) 3 afford mono- and bis-chelate complexes [RuCl(η 6- p-cymene){η 2-Ph 2P{(-OC 10H 6)(μ-CH 2)(C 10H 6O-)}PPh 2-κP,κP}]Cl ( 2) and trans-[RuCl 2{η 2-Ph 2P{(-OC 10H 6)(μ-CH 2)(C 10H 6O-)}PPh 2-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){η 2-Ph 2P(-OC 10H 6)(μ-CH 2)(C 10H 6O-)PPh 2-κP,κP}] ( 4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN) 4]PF 6 affords a bis-chelated cationic complex [Cu{η 2-Ph 2P(-OC 10H 6)(μ-CH 2)(C 10H 6O-)PPh 2-κP,κP} 2][PF 6] ( 7). Reaction between 1 and AgOTf produce both mono- and bis-chelated complexes [Ag{η 2-Ph 2P(-OC 10H 6)(μ-CH 2)(C 10H 6O-)PPh 2-κP,κP}(SO 3CF 3)] ( 8) and [Ag{η 2-Ph 2P(-OC 10H 6)(μ-CH 2)(C 10H 6O-)PPh 2-κP,κP} 2][SO 3CF 3] ( 9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh 3] affords chelate complex of the type [Ag{η 2-Ph 2P(-OC 10H 6)(μ-CH 2)(C 10H 6O-)PPh 2-κP,κP}(PPh 3)(SO 3CF 3)] ( 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.