Polycarbon ligand chemistry: Electronic interactions between a mononuclear ruthenium fragment and a cobalt-carbon cluster core

The preparation, characterization, and electrochemical response of the complexes Co-2(mu-Me3SiC=CC2C=CSiMe3)(CO)(4)(dppm) (2) and Co-2(mu-Me3SiC2C=CC=CSiMe3)(CO)(4)(dppm) (3) are described. Metalation of one of the pendant alkynyl groups in each complex has been achieved, yielding Co-2{mu-Me3SiC=CC2C=C[Ru(PPh3)(2)Cp]}(CO)(4)(dppm)(4) and Co-2{mu-Me3SiC2C=CC=C[Ru(PPh3)(2)Cp]}(CO)(4)(dppm) (5). The spectral and electrochemical properties of the heterometallic complexes indicate a significant electronic interaction between the mononuclear fragment and the metallocarbon cluster core. The electronic structure of these compounds has been modeled using DFT, ZINDO, and ELF calculations, and an explanation of the nature of the electronic interaction between the heterometallic fragments is presented.