Mixed-Valent Linear Chains of Gold Atoms. X-Ray Structure of [{(2,4,6-C6F3H2)Au(CH2PPh2CH2)2Au}2Au(CH2PPh2CH2)2Au](ClO4)2

Resumen

Reactions of asymmetrical gold(II) derivatives [RAu(CH2PPh2CH2)2AuX] (R = C6F5, 2,4,6-C6F3H2; CH3, X = halogen) with AgClO4 lead to the compounds [RAu(CH2PPh2CH2)2AuOClO 3], which further react with NBu4[AuR2] (R = C6F5, C6F3H2) or [Au(CH2PPh2CH2)2Au] to give pentanuclear [{RAu(CH2PPh2CH2)2Au} 2AuR2]ClO4 or hexanuclear [{RAu(CH2PPh2CH2)2-Au} 2Au(CH2PPh2CH2) 2Au](ClO4)2 gold complexes in different oxidation states. The same results can be achieved if the reactions are carried out with [RAu(CH2PPh2CH2)2Au(tht)]ClO 4 (tht = tetrahydrothiophene). The structure of [{(2,4,6-C6F3H2)Au(CH2PPh 2CH2)2Au}2Au(CH2PPh 2-CH2)2Au](ClO4)2 has been determined by a single-crystal X-ray diffraction study. It crystallizes in the monoclinic space group P21/c with a = 12.150(1) Å, b = 15.498(2) Å, c = 24.693(2) Å, β = 95.18(1)°, Z = 2, R = 0.0404, and Rw = 0.0417 for 5132 observed reflections. The centrosymmetric cationic complex exhibits a linear hexametallic skeleton and is composed of three pairs of gold atoms, each of them doubly bridged by two bis-ylide ligands. Two σ-bonded C6F3H2 groups complete the coordination of the external gold centers. The three "Au(CH2PPh2CH2)2Au" moieties are held together through two unbridged Au-Au direct bonds (2.7370(7) Å), with the ligand-bridged Au-Au separations at 2.6540(7) and 2.8378(7) Å. 1994 American Chemical Society.