Abstract

Chhandasi Guharoy Sarkar

DOI : http://dx.doi.org/10.13005/ojc/320313

Reaction of bis-2,3-(2-pyridyl)pyrazine (L) with [Ru(dmso)₄Cl₂] in presence of 4-picoline (L₁) affords mixed- ligand complexes of the type [Ru₂L(L₁)₄Cl₄] in which ligand, L binds to the metal center in the bridging, bidentate N,N fashion forming two five-membered chelate rings. Along with [Ru₂L(L₁)₄Cl₄], another complex of the type [Ru(L₁)₂(dmso)₂Cl₂] is formed. All the complexes are diamagnetic, and show characteristic ¹H NMR signals and intense MLCT transitions in the visible region. DFT studies reveal that the HOMO of the complexes is mostly based on the metal center while the LUMO has maximum contribution from the bonded 4-picoline ligand. Cyclic voltammetry on these complexes shows a Ru(II)-Ru(III) oxidation on the positive side of SCE followed by a reduction of the coordinated 4-picoline ligand on the negative side of SCE.

bis-2,3-(2-pyridyl)pyrazine; [Ru(dmso)4Cl2]; spectral and electrochemical properties; DFT studies

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