Synthesis, single crystal structure, NBO investigations, and Hirshfeld topology analysis of new ethyl-5,8-dimethyl-6-phenyl-(1H-pyrrol-1-yl)-6,7-dihydrothieno[2,3-c]isoquinoline-2-carboxylate

Abstract

Ethyl-5,8-dimethyl-6-phenyl-(1H-pyrrol-1-yl)-6,7-dihydrothieno[2,3-c]isoquinoline-2-carboxylate has been synthesized and single-crystal X-ray diffraction at 170 K and DFT calculations were performed to characterize the reactivity and its electronic structure. The asymmetric unit of the title molecule, C26H24N2O2S, contains two independent molecules differing primarily in the rotational orientations of the pyrrolyl substituent. The two independent molecules are connected by a C—H···O hydrogen bond and in the crystal, two asymmetric units are linked by inversion-related C—H···N hydrogen bonds. The Hirshfeld surface (HS) analysis reveals intermolecular interactions and surface reactivity in a single crystal. The highest fraction of intermolecular contact of 64% can be seen for H⋅⋅⋅H while the lowest contribution of 3.9% was observed for O⋅⋅⋅H contact in crystal packing. The interaction energies between chemical pairs in the crystal structure are investigated by energy framework analysis which indicates repulsion outweighs the coulomb energy and dispersion energy. The performed density functional theory (DFT) investigation has provided us an electronic picture the of structure and fabulous reactivity. The frontier molecular orbital (FMO) analysis reveals a narrow HOMO-LUMO gap (3.81 eV) and global reactivity descriptors also agree with molecular reactivity and remarkable electronic properties. The density of state (DOS) study shows a pictorial representation the of density of states while MESP shows reactive sites (electron-rich) of the compound for electrophilic attack.