Binuclear chiral Ni(II) complex of tridentate OON chiral Schiff base ligand, 1-((E)-(((1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl)imino)methyl)naphthalen-2-ol

Abstract

Binuclear Ni(II) chelating complex with chiral Schiff base 1-((E)-(((1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl)imino)methyl)naphthalene-2-ol [Ni2L2] has been synthesized. The structure of [Ni2L2] was elucidated with single-crystal X-ray diffraction, spectroscopic (UV–vis, FTIR, mass) analysis and substantiated with computational (DFT) method. The crystal system of binuclear complex is monoclinic with space group P21/c. The asymmetric unit having two tridentate OON-donor sets are in slightly distorted square-planar geometry around each Ni(II) center. The distortion is due to strong coordination between two Ni(II) ions. The stabilization of complex [Ni2L2] occurs due to noncovalent interactions and hydrogen bonding (C–H…C and C–H…O), H…H, O…H, C…H, and C–H…π stacking interactions, and van der Waals interactions. DFT optimization, with little acceptable discrepancies, correlate with the X-ray diffraction data as well as TD DFT optimization for electronic transitions of the complex showing acceptable alignment with spectroscopic data. The complex displays appreciable inclination towards DNA-binding with calf-thymus DNA (CT DNA) and the DNA-binding studies were carried out by UV–visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry, viscosity measurements, and CD spectroscopy. The DNA-binding study reveals that the order of binding constant value is in 105 M−1, supporting the effective efficiency of binding and the modes of binding are intercalation and groove.