Unsymmetrical Structure of the Co(III) Complex with Bisheteroarylhydrazone as Hydrazone and Quinolone Tautomers Stabilized by Hydrogen Bond

Bisheteroarylhydrazone (H 2 L), the product of 2-hydrazinoquinoline condensation with diacetyl, and mononuclear Co(III) complex [Co(HL) 2 ]Br·2DMSO ( I ) based on this ligand were synthesized. The structure of the chelate was determined by X-ray diffraction (CIF file CCDC no. 2099899). The Co(III) ion in I occurs in the low-spin state and has a slightly distorted octahedral coordination unit. The two monodeprotonated bisquinolylhydrazones in the chelate function as tridentrate ligands in different tautomeric forms stabilized by interligand intramolecular hydrogen bond.