Experimental and theoretical approaches to the reactions of ruthenium-4,4′-dimethyl-2,2′-bipyridine carbonyl complexes

The reactions of ruthenium-4,4′-dimethyl-2,2′-bipyridine (4,4′-dmbpy) carbonyl complexes were investigated by experimental and computational methods. The reaction route from [Ru(CO)3Cl2]2 and 4,4′-dmbpy in ethylene glycol proceeded in several consecutive steps to dimeric [Ru(4,4′-dmbpy)(CO)2Cl]2. The intermediates in each step were isolated and characterized using spectroscopic methods. Total reaction energies were calculated by non-local density functional methods. Electron donating methyl groups have been suggested to cause changes in the electronic environment of the ruthenium central atom, thus affecting the catalytic properties of these complexes. The reactions of ruthenium-4,4′-dmbpy complexes in ethylene glycol were compared to the related reactions of analogous ruthenium-2,2′-bipyridine complexes in order to determine the influence of peripheric methyl substituents on the reactivities of the complexes.