A comparative study on metal-metal interaction in binuclear two- and three-coordinated d10-metal complexes spectroscopic investigation of M(I)-M(I) interaction in the 1[d(dσ*pσ] excited state of [M2(dcpm)2]2+ (dcpm = bis(dicyclohexylphosphino)methane) (M = Au, Ag, Cu) and [M2(dmpm)3]2+ (dmpm = bis(dimethylphosphino)methane) (M = Au, Ag, Cu) complexes

An overview of an UV-vis spectroscopic and resonance Raman investigation of the lowest energy dipole-allowed absorption band of [M-2(dcpm)(2)](2+) (M = Au, Ag, Cu) and [M-2(dMPM)(3)](2+) (M = Au, Ag, Cu) complexes is presented. The UV-vis absorption spectra of [M-2(dCPM)(2)](2+) and [M-2(dmpM)(3)](2+) feature intense low energy nd sigma* -> (n + 1)p sigma transition with transition energy increase from two- to three-coordinated complexes and for [M-2 (dcpm)(2)](2+) falls in the order: Ag > An > Cu. A resonance Raman intensity analysis of the spectra allows estimation of the structural changes of the (1)[d sigma*p sigma] excited states relative to the ground state. The structural changes in these compounds are compared with each other and with other related compounds. The metal-metal bonds are found to be very similar for the ground and excited states of the [Au-2(dcpm)(2)](2+) and [Au-2(dmpm)(3)](2+) complexes but significantly different for the [Cu-2(dcpm)(2)](2+) and [Cu-2(dmpm)(3)](2+) complexes that have weaker metal-metal bonding. (c) 2004 Elsevier B.V. All rights reserved.