Molecular Structure Investigation, Charge Transfer Interactions, Hirshfeld Surface analysis and Molecular Docking of 2’-(4-bromobenzoyl)- 1’-(2-chlorophenyl)-1,1’,2,2’,5’,6’,7’,7a’-octahydro-spiro[indole-3,3’- pyrrolizin]-2-one using Quantum chemical comp

Abstract

Indole and its derivatives take up a key position in the field of medicinal chemistry due to its
various pharmacological activities. The molecule of interest 2’-(4-bromobenzoyl)-1’- (2-
chlorophenyl)-1,1’,2,2’,5’,6’,7’,7a’-octahydro-spiro[indole-3,3’-pyrrolizin]-2-one has been
subjected to DFT (Density Functional Theory) studies in order to elucidate the electronic structure.
The title molecule has been optimized using Gaussian ‘09 program. NBO analysis reveals the
existence of C ̶ H···O intramolecular interactions, which are well reflected by the amount of charge
transferred from n(O13) → σ* (C6– H11) with the stabilization energy of 2.53 kcal/mol. Molecular
electrostatic potential (MEP) image shows the most electronegative region indicated by red color
around the oxygen atom is the potential binding site. The low energy gap (ΔE 3.2786 ev) observed
from the Frontier molecular orbital analysis shows the molecule to be biologically active. Hirshfeld
Surface analysis and 2D fingerplot substantiates the presence of intermolecular interactions that
arises within the crystal packing. Molecular simulation carried out using AUTODOCK 4.2 reveals
optimized structure of the ligand has been docked in the binding site of severe acute respiratory
syndrome related corona virus protein.