Structure and Photochemical Isomerization of the Dinuclear Gold(I) Halide Bis(diphenylphosphanyl)ethylene Complexes: Correlation Between Quantum Yield and Aurophilicity

The crystal structures for cis‐ (Ph 2 PCH=CHPPh 2 )(AuI) 2 and trans‐ (Ph 2 PCH=CHPPh 2 )(AuI) 2 are reported. The structure of cis‐ (Ph 2 PCH=CHPPh 2 )(AuI) 2 reveals a short intramolecular Au–Au distance of 2.9526(5) Å, while the structure of trans ‐(Ph 2 PCH=CHPPh 2 )(AuI) 2 shows intermolecular Au–Au distances of 3.2292(7) Å. Structural data for the iodide complexes are compared to previously reported crystal structural data for cis‐ and trans ‐(Ph 2 PCH=CHPPh 2 )(AuCl) 2 and dppbz(AuCl) 2 . The quantum yields for the photochemical isomerization of cis ‐(Ph 2 PCH=CHPPh 2 )(AuX) 2 with 334‐nm light, Φ ( cis → trans ), are 0.204, 0.269, and 0.363 for X = Cl, Br, and I, respectively. Prior results from ab initio calculations on the model cis ‐ and trans ‐Au 2 X 2 C 2 H 2 (PH 2 ) 2 complexes aid in the interpretation of the correlation between the quantum yield for isomerization and the calculated aurophilic attraction potential V ( R e ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)