Structural-property relationship in halogen-bonded Schiff base derivative: Crystal structure, computational and SARS-CoV-2 docking studies

Abstract

We synthesized the halogenated Schiff base compound to understand the influence of halogen and hydrogen bonding interactions. The Schiff base compound is characterized by FTIR, SEM-EDAX and single-crystal X-ray diffraction studies. The structural studies reveal that the 4-chloro-2-(((4-chlorobenzyl) imino) methyl) phenol crystallizes in the monoclinic, P21/n space group. The O1-H1‧‧‧N1 strong hydrogen bond forms the intramolecular pseudo chelating ring motif and acts as a coordinating site for metal complexes. The intra, intermolecular and π‧‧‧π interactions were involved in the construction of supramolecular architecture. The interesting type-I halogen bonds having trans geometry are exhibited. Hirshfeld surface analysis supports the interactions observed in the crystal structure, and the energy framework analysis provides the stabilization interaction energy among the molecular pairs. The enrichment ratio provides favored contacts between the atomic pair and gives strong validation to the halogen‧‧‧halogen and halogen‧‧‧hydrogen bonds. The DFT studies give more insight into electronic structure and provide a global and local parameter of the molecule. NBO studies provide stabilization energy and charge transfer within the molecule. The QTAIM studies were used to calculate the strength of the halogen, hydrogen and stacking intermolecular interaction. Further, docking studies were carried out for COVID-19 proteins to reveal the structural-function properties of halogen and hydrogen bonds present in the synthesized compound.