Synthesis, molecular structure, mesomorphism and DFT/TD-DFT calculations of square-planar bis[1-((p-tolylimino)methyl) naphthalen-2-olato-c2N,O]nickel and copper(II) complexes

Reaction of the Schiff base ligand (E)-1-((p-tolylimino)methyl)naphthalen-2-ol (HL) with nickel(II) and copper (II) acetate provides the bis[1-((p-tolylimino)methyl)naphthalen-2-olato-c2N,O]Ni and Cu(II) complexes (1 and 2), respectively. X-ray structure determinations reveal coordination of two N,O-chelate Schiff base ligands to the metal ion in a square-planar geometry for both the complexes. The phase purity of bulk microcrystalline samples is confirmed by Powder XRD patterns. The solid-state magnetic moment (& mu;eff = 2.73 (1) and 2.06 & mu;B (2)) indicates paramagnetic nature of the complexes. Thermal analyses by differential scanning calorimetry (DSC) and polarizing light microscopic (PLM) observations suggest mesomorphic property for 2. Cyclic voltammograms recommend a quasi-reversible two one electron charge transfer processes for 2 in dimethylformamide. Geometry optimization and excited state properties by DFT/TD-DFT calculations reproduce the experimental bond distances and angles as well as the experimental electronic spectra.