Water‐Encapsulated Ni(II) Salphen‐Type Host Complexes: Experimental and Theoretical Analysis of Potentially Bioactive Quasi‐Isostructural Polymorphs

Abstract

AbstractIn this study, we report the formation of two quasi‐isostructural polymorphs (α and β) of a Ni(II) salphen‐type Schiff base complex using solvent evaporation technique. The polymorphs are inclusion compounds with guest water molecules exhibiting similar spectroscopic and thermal characteristics. Single crystal XRD (X‐ray Diffraction) analyses reveal the subtle differences in packing and supramolecular interactions which are quantified using Hirshfeld and 2D finger print analyses. Electrostatic potential analysis shows significant difference in potential distribution in the two molecules. The compositional analysis of the frontier orbitals and differences among the atomic charge distribution of the polymorphs are established using DFT (Density Functional Theory) calculations. Apart from highlighting the strength of encapsulation, DFT study substantiates the formation of inclusion compounds through single point energy calculations. Effects of inherent differences in the polymorphs on potential biological activity are probed using in silico molecular docking with B‐DNA and Human Serum Albumin (HSA). The α form shows superior bioactivity while β form excels in water encapsulation.