Substituent effects on aurophilicity and π-π interaction in crystals of arylphosphine-Au(I) derivatives.: Synthesis and X-ray structural studies of compounds (CX3C6H4)3P-Au-X and {(CF3)2C6H3}3P-Au-X

Substituent effects on aurophilic interactions have been explored by single-crystal X-ray diffraction methods for a series of Au(I) complexes of monodentate phosphines, R-3'P-Au-X (X = Cl, Sph, and Spy). When a CF3 substituent is introduced at a meta position of the phenyl ring in (C6H5)(3)P, aurophilicity has been accrued in ClAuP(m-CF3C6H4)3, However, aurophilicity has been weakened by introducing two CF3 groups at both meta positions. When a CF3 substituent is substituted for a H atom in the para position or when a CH3 substituent is introduced in the meta and/or para positions, such an effect has not been observed for R-3'PAuCl and R-3'PAuSph. Most dimers constructed by aurophilicity appear to be reinforced by pi-pi interactions between the phenyl ring of the Sph ligand or the pyridine ring of the Spy ligand and one of the phenyl rings in the R-3'P ligand. A novel ladder-like supra molecular architecture is created in the crystal of {3,5-(F3C)(2)C6H3}(3)PAuSph, and a tetramer is formed in the crystal of (C6H5)(3)PAuSpy by aurophilic and pi-pi interactions. Substituent effects on important bond lengths have been discussed. (C) 2001 Elsevier Science B.V. All rights reserved.