Dinuclear Gold(I) Chloride Complexes of 1,4-Bis(diphenylphosphinyl)butane and 1,5-Bis(diphenylphosphinyl)pentane: A Conformational Study

Abstract

[1,4-Bis(diphenylphosphinyl)butane]digold dichloride 1 and [1,5-bis(diphenylphosphinyl)-pentane]digold dichloride 2 have been prepared from R 2 SAuCl (R = CH 2 CH 2 OH) and the corresponding bidentate phosphines Ph 2 P(CH 2 ) n PPh 2 (n = 4 or 5) in good yields. The structures of the compounds have been determined by single crystal X-ray diffraction (1 · CH 2 C1 2 : space group P1̅, Z = 2; 2·0.5 CH 2 Cl 2 : space group C 2/c, Z = 8). While the monomers [Ph 2 P(CH 2 ) 5 PPh 2 ] (AuCl) 2 are associated through intermolecular Au···Au contacts (3.323 Å) to form a chain-like structure, the crystal lattice of 1· CH 2 Cl 2 features independent [Ph 2 P(CH 2 ) 4 PPh 2 ](AuCl) 2 molecules which show no intra- or intermolecular Au···Au interactions. This exceptional behaviour can be rationalized on the basis of efficient packing of solvent molecules and molecules 1 with a particularly favourable conformation, which cannot be altered by weak Au(d 10 )—Au(d 10 ) interactions.