Abstract
To explore the metal–metal interaction and spectroscopic properties, the ground‐ and excited‐state structures of [M~2~(dpm)~2~]^2+^ [M = Ag (2), Cu (3), dpm = bis(diphosphanyl)methane] and their solvated species [M~2~(dpm)~2~]^2+^·(MeCN)~2~ were optimized by the MP2 and CIS methods, respectively. In the ground states, the calculated M–M distances and their corresponding M–M stretching frequencies for 2 and 3 indicate the presence of metallophilic attraction; there is strong N→Cu/Ag coordination in acetonitrile, which is different from the case in previous studies of [Au~2~(dpm)~2~]^2+^ (1). CIS calculations show that 2 and 3 have ^1,3^[σ*(d)σ(s/p)] as their lowest‐energy excited state, as is also the case for 1, confirmed by unrestricted MP2 calculations. On the basis of the CIS‐optimized structures, the TD‐DFT (B3LYP) method was employed to calculate the emission spectra of such complexes. For 3, the phosphorescent emissions were calculated at 424 and 514 nm in the solid state and acetonitrile, which is comparable to the experimental data of 475 and 480 nm, respectively. The comparison between the gas‐phase and solution emissions for 1–3 reveals that the N→M coordination results in a large red‐shift of the emission wavelength. Taking previous studies into account , we found that the M–M distances are linearly correlated with the M–M stretching frequencies for the dinuclear d^10^ complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)