The observation of isocyano cobalt (III)-Schiff base complexes

Abstract

[Abstract] Two isocyano-coordinated cobalt(III)-Schiff base complexes, [Co(L1)(CH_3OH)(NC)]・CH_2Cl_2 (1) and [Co(L2)(H_2O)(NC)]•CH_2Cl_2 (2) (H_2L1＝ N,N-disalicylidene-2,3-naphthalenediimine, H_2L2 ＝ N,N-bis(3-methoxysalicylaldehyde)-1,2-phenylene-diimine), were synthesized from the reaction of TCNQ and corresponding planar cobalt(II) complexes 3 and 4, respectively. The single-crystal X-ray diffraction analysis of the crystals clearly shows the coordination of C1^- moiety to the Co(III) complex. The characterization of products by the FT-IR and C^ NMR measurements indicate the coexistence of two isomers, isocyano and cyano complexes, both in the solid state and in solution. The DFT calculations on the isomerization reaction (ΔH_: -42.6 kJ mot^, E_a: 121.3 kJ mol^) indicate the difficulty of the reaction at room temperature, which is in accordance with the observation of the two isomers