Two new copper(II) complexes with the shortest (N–N) diazine based rigid ligand: Example of unusual tridentate coordination mode

Two new five coordinated Cu(II) complexes, Cu(L)Cl2,CH3OH (1) and Cu(L)Br2 (2) derived from the flexidentate ligand (L), 2-pyridinealdazine, have been synthesised and characterised by spectroscopic and electrochemical studies. Single crystal structures of the complexes were determined. Crystal structures of both the complexes contain monomeric entities of five coordinated copper(II) ions where the Schiff base ligand, 2-pyridinealdazine, acts in a tridentate fashion. The central part of the ligand in complex 2 is disordered over two positions: N8N9 make up the major position and N8AN9A make up the minor position.