An insight to the role of perchlorate counter ions and different non-covalent interactions in the solid state structures of mono-anionic malonic acid bridged trinuclear mixed valence cationic complexes of cobalt with tetradentate N2O2 donor ligands

Abstract

Two linear mixed-valence trinuclear centrosymmetric cobalt(III)-cobalt(II)-cobalt(III) complexes, [CoII{(μ-L1)(μ-OOCCH2COOH)CoIII(DMF)}2](ClO4)2⋅2DMSO (1) and [CoII{(μ-L2)(μ-OOCCH2COOH)CoIII(DMF)}2](ClO4)2⋅2DMSO (2) have been synthesized using tetradentate N2O2 donor ‘reduced Schiff base’ ligands, H2L1 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(phenol) and H2L2 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(4-chlorophenol), and malonic acid as anionic co-ligand. The complexes have been characterized by spectroscopic measurements and their solid state structures have been determined by single crystal X-ray diffraction analysis. Some supra-molecular assemblies observed in the solid state structures of both complexes have been analysed using DFT calculations, in particular CH3···π and Cl···Cl interactions. QTAIM and NCI Plot computational tools have been used to characterize the interactions.