Abstract

CARUSO, F.; ROSSI, M; OPAZO, C  and  PETTINARI, C.. Structural features of antitumor gold(I)-phosphine derivatives analyzed with theoretical methods. An. Asoc. Quím. Argent. [online]. 2004, vol.92, n.1-3, pp.119-124. ISSN 0365-0375.

A Density Functional Theory (DFT) analysis of the mixed phosphine complexes Au(PPh3)(Ph2P(CH2)3PPh2)X shows a clear trend in the metal geometry as the anion X- is varied: the softer the anion, the more it is tetrahedral, or alternatively, the more ionic the complex, the more the complex geometry approaches trigonal planar. A strong (soft) donor as cyanide (X- = CN-) penetrates markedly the coordination sphere and establishes the most tetrahedral geometry. In the antitumor compound Au(PPh3)(Ph2P(CH2)3PPh2)Cl (X- = Cl-), the weaker donor chloride is slightly displaced from the coordination sphere with consequent strengthening of Au-P bonds, thus stabilizing a more pyramidal geometry. If the anion is completely out of the coordination sphere, the cation [Au(PPh3)(Ph2P(CH2)3PPh2)]+ shows further strengthening of Au-P bonds and a geometry very close to the trigonal planar "AuP3" system. X-ray and DFT data for Au(PPh3)(Ph2P(CH2)3PPh2)Cl show generally good agreement; however, in the crystal the Au-Cl bond appears lengthened with consequent strong Au-P bonds. This is probably due to packing effects; nevertheless, the X-ray structure agrees with the trend mentioned above as well.

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