Design and synthesis of dinuclear cobalt(ii) complexes derived from strong π-acidic ligands: crystal structure and studies on the oxidation of sp3 C–H bonds

Abstract

In this work, cobalt complexes 1 and 2 were synthesized from ligands L¹ (1,2-bis(2-phenyl-2-(pyridin-2-yl)hydrazineylidene)ethane) and L² (1,2-bis(2-(pyridin-2-yl)hydrazineylidene)ethane) in moderate yields. These complexes were characterized by UV-visible, IR and ESI-MS spectroscopic studies. The molecular structure of complex 1 was determined by X-ray crystallography. Complexes 1 and 2 were employed as catalysts for the oxidation of sp³ C–H bonds. A total of 12 substrates were investigated for the oxidation of benzylic and aliphatic sp³ C–H bonds. A reaction pathway was proposed and possible reactive intermediate species was successfully characterized by ESI-MS spectroscopic studies.