Dinuclear gold(I) and silver(I) derivatives with bridging phosphines containing an imidazole ring; X-ray crystal structure of (1-benzyl-2-imidazolyl)diphenylphosphinegold(I)chloride

Abstract

(1-Benzyl-2-imidazolyl)diphenylphosphine [(BzIm)Ph 2P] can act as a monodentate or bidentate ligand to afford mononuclear (BzIm)Ph 2PAuCl ( I) or dinuclear [μ-(BzIm)Ph 2PAu] 2 2+ 2X − (X = PF 6 −, BF 4 − or NO 3 −) ( IIa,b,c) derivatives of gold(I). Analogous dinuclear silver(I) derivatives were obtained reacting the ligand [(BzIm)Ph 2P] with AgX salts (X = NO 3 −, BF 4 −) ( IIIa,b). In solution the silver complexes show a fluxional behaviour, and two conformers were observed by 31P NMR spectroscopy. The structure of compound I was established by X-ray crystallography (monoclinic, space group C2/c, a = 18.068(2), b = 16.576(2), c = 15.391(2) A ̊ , β = 117.2(2)°, Z = 8) . The short intermolecular Au⋯Au distance of 3.03(2) Å indicates a metal-metal interaction. The 197Au Mössbauer parameters of compounds I and IIa are consistent with IR, NMR and crystallographic data.