Electronic communication between carbon chain bridged metals: a theoretical approach. Even Chains

A theoretical investigation (DFT) allowed us to single out the most appropriate valence structure for the [M-C-x-M] unit in a variety of model compounds [{Cp(CO)(2)M}(2)(mu-C-x)] (M = Cr, Mn or Fe; x = 2-8) and to foresee it on the basis of the molecular parameters, such as (i) the chain length, () the nature of the metal and its oxidation state, (iii) the d " configuration and the metal co-ordination number. The valence structure of the [M-C-x-M] unit is diagnostic of the metal-to-metal communication. A simple electron-counting scheme has been developed to predict the valence structure, based on the d " configuration of the MLm fragments and the number of electrons of the linear C-x unit.