Synthesis and transition metal chemistry of a bridging diphosphinite, 1,4 bis(diphenylphosphinoxy)benzene

Abstract

Diphosphinite ligand, [Ph 2POC 6H 4OPPh 2] ( 1), is obtained by reacting chloro diphenylphosphine, with 1,4-dihydroxy benzene in presence of triethylamine. Treatment of 1 with elemental sulfur or selenium resulted in the formation of bis(chalcogenide) derivatives, [Ph 2(E)POC 6H 4OP(E)Ph 2] ( 2, E = S; 3, E = Se) in almost quantitative yield. The binuclear complex [{( η 6- p-cymene)RuCl 2} 2(Ph 2POC 6H 4OPPh 2)] ( 4) is produced in the reaction between [Ru( η 6- p-cymene)Cl 2] 2 and diphosphinite 1. Similarly the reaction of 1 with [Rh(COD)Cl] 2 afforded a binuclear complex [{(COD)RhCl} 2(Ph 2POC 6H 4OPPh 2)] ( 5), whereas the macrocyclic complex [{(CO)RhCl}(Ph 2POC 6H 4OPPh 2)] 2 ( 6) is isolated in the reaction of 1 with 0.5 equiv of [RhCl(CO) 2] 2. Compound 1 on treatment with [Pd(COD)Cl 2] or [PdCl 2(SMe 2) 2] in 1:1 molar ratio produced the chloro-bridged binuclear complex [{(PPh 2O)Pd( μ-Cl)(PPh 2OH)} 2] ( 7) through P–O bond cleavage. Treatment of 1 with two equivalents of CuI in dichlormethane/acetonitrile (1:1) afforded a coordination polymer, [{Cu 2( μ-I) 2(Ph 2POC 6H 4OPPh 2)} ∞] ( 8) in moderate yield. The binuclear complex, [{AuCl} 2( μ-Ph 2POC 6H 4OPPh 2)] ( 9) is obtained in the reaction of compound 1 with two equiv of AuCl(SMe 2), where the ligand exhibits bridged bidentate mode of coordination. The molecular structures of 1– 4, and 6 are determined by X-ray diffraction studies.