Steric effects and geometrical distortions on a new series of cobalt(II) entwined complexes: stabilization of low valent oxidation states, cobalt(I) and cobalt(O) complex species

Abstract

Cobalt(II) complexes of 2,9-disubstituted and 2-monosubstituted 1,10-phenanthrolines by phenyl moieties containing ortho substituents were prepared and investigated by electronic spectral and electrochemical methods. Larger ortho substituents are found to cause more tetrahedral distortions, while the absence of substitution at the 9-position of the phenanthroline leads to smaller distortions. The tetrahedral distortion imposed by the bulkiness of the ligands and the weakly interacting forces mediated through the ortho substituents of the phenyl with the central metal ion influences the electrochemical reductions and also leads to stabilized cobalt(I) and cobalt(O) complex species.