Crystal Structure of 2,2,2′,2′-Tetraaurated Diphenylethane [2-(AuPPh3)2C6H4]-(CH2)2-[2-(AuPPh3)2C6H4](BF4)2

The salt [2-(AuPPh(3))(2)C(6)H(4)]-(CH(2))(2)-[2-(AuPPh(3))(2)C(6)H(4)](BF(4))(2) was studied by X-ray diffraction analysis (Siemens CCD SMART diffractometer, graphite monochromator, T = 150.0(2) K, theta(max) = 27.5 degrees, R = 0.0852 for 6519 reflections), and its crystal and molecular structures were determined. The crystals are triclinic, a = 10.2481(2), b = 12.8884(2), c = 16.3794(2) angstrom, a = 94.715(1)degrees, beta = 102.114(1)degrees, gamma = 110.100(1)degrees, V = 1958.15(5) angstrom(3), Z = 1, space group P (1) over bar. The crystal is built of the centrosymmetric doubly charged [2-(AuPPh(3))(2)C(6)H(4)]-(CH(2))(2)-[2-(AuPPh(3))(2)C(6)H(4)](2+) cations and BF(4)(-) anions. The central dipenylethane fragment has a strictly planar transoid structure. One of the ortho positions of each Ph ring is doubly aurated. The Au center dot center dot center dot Au distance of 2.7440(8) angstrom in the CAu(2) triangle and the AuCAu angle of 78.3(5)degrees correspond to the strong aurophilic interaction. The triangular CAu(2) fragment is almost perpendicular to the plane of the benzene ring. The deviations of the Au atoms from the plane of the benzene ring are 1.629 and -1.084 angstrom. The distance between each Au atom and the nearest H atom of the ethylene bridge (2.88 and 2.71 angstrom) corresponds to the agostic interaction.