Chemical assessment of three octahedral Ni(II) complexes with heterocyclic acylpyrazolone ligand: Crystal structure, DFT-NBO analysis, Hirshfeld and Magnetic study

Abstract

We have synthesized three novel mononuclear Nickel(II) coordination complexes [Ni(DMBPTMP)2(EtOH)2], [Ni(PCBPMP)2(DMF)(H2O)] and [Ni(PCBPTMP)2(DMSO)2] with σ-donating acylpyarazolone ligands. All the complexes have been comprehensively characterized via FTIR, UV–Vis, TGA, and Magnetic study. Additionally, single crystal X-ray diffraction analysis was successfully used to characterize the three complexes. The findings showed that the geometry around Ni(II) is slightly distorted octahedral in [Ni(DMBPTMP)2(EtOH)2], [Ni(PCBPMP)2(DMF)(H2O)] complexes and also in the centrosymmetric [Ni(PCBPTMP)2(DMSO)2] complex. In all the complexes the metal is bischelated by two pyrazolone molecules via carbonyl and benzoyl carbonyl oxygen donors, but with a different configuration of ligands. In addition to the experimental studies and spectroscopic characteristics, DFT computational analysis and Natural bonding orbital (NBO) analysis have been performed using a B3LYP/LANL2DZ basis set for the optimization. All three Ni(II) complexes give three distinct absorption transitions which has been proved by Electronic spectral analysis. A paramagnetic nature of the complex is confirmed through magnetic study. Utilising Hirshfeld surface analysis, intermolecular interactions of complexes were evaluated.