Change in the Tautomeric Form of 1,1′-Azinobis(3,3-Dimethyl-3,4-Dihydroisocarbostyril) upon Coordination to Cobalt(II): Crystal Structure and Spectra of [CoLCl2] · C3H6O

The complex [CoLCl2] · C3H6O (I), where L is 1,1′-azinobis(3,3-dimethyl-3,4-dihydroisocarbostyril) and C3H6O is acetone, was synthesized. The crystal structure of I was determined by X-ray diffraction analysis. It was found that upon incorporation into the complex, the ligand L passes from the azine tautomeric state to the azine-hydrazine state. The bidentate chelating ligand L in I is linked to the metal via the endocyclic and exocyclic nitrogen atoms giving a five-membered chelate ring. The IR and electronic absorption spectra of complex I and the possible mechanism of its formation are discussed.