Does metallophilicity increase or decrease down group 11? Computational investigations of [Cl-M-PH3]2 ( M = Cu, Ag, Au, [111])

The electronic and geometric structures of Cl - M - PH3 and [Cl - M - PH3](2) (M = Cu, Ag, Au, [111]) have been studied computationally using post Hartree - Fock ab initio and density functional methods. The trends in r(M - Cl) and r(M - P) in the monomers are discussed in the light of previous studies. Previous MP2 data on the metallophilic interactions in [Cl - M - PH3](2) (M = Cu, Ag, Au) are reproduced ( to within basis set differences), and new MP2 data for the transactinide element 111 are presented. QCISD and coupled cluster calculations on the title systems are reported for the first time, and reveal that, contrary to the MP2 results, the strength of the metallophilic interaction essentially decreases as group 11 is descended.