Harnessing of non-covalent interaction in novel [Ni(en)3](2-chlorophenylacetate)2 second sphere complex: Synthesis, characterization, single crystal structural, DFT, and Hirshfeld surface analysis

Novel nickel(II) ethylenediamine compound, [Ni(en)3](2-chlorophenylacetate)2, has been synthesized and characterized by spectroscopic techniques (UV-vis, FT-IR), thermogravimetric analysis, magnetic moment, molar conductivity measurement, and single-crystal X-ray diffraction analysis. The complex crystallizes in a triclinic crystal system with P 1 space group with cell dimensions of a = 8.9050(2), b = 12.5620(4), c = 14.0590(4) Å, α = 102.259(2)°, β = 107.172(2)°, and γ = 106.914(2)°. The complex consists of [Ni(en)3]2+ as the cationic part and two discrete 2-chlorophenylacetate ions as anionic counterparts divulging the existence of a second sphere complex with distorted octahedral geometry. Besides electrostatic forces of attraction, non-covalent interactions (hydrogen bonding and C-H…π) sew the second sphere in extended three-dimensional supramolecular architecture and provide robustness to the crystal lattice. Field electron scanning microscope (FESEM) and energy dispersive X-ray spectra (EDX) were employed to study the surface morphology of the structure. To explore the structural insights and bonding in the complex theoretical studies, i.e., density functional theory (DFT) and Hirshfeld surface analysis have also been employed.