Crystal structure studies, Hirshfeld surface analysis and DFT calculations of novel 1-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]-piperazine derivatives

Abstract

Abstract Two new compounds 1-(4-tert-butyl-benzenesulfonyl)-4-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]-piperazine (I) and 1-[5-(4-methoxyphenyl)-[1,3,4]oxadiazol-2-yl]-4-[(4-bromo)benzene sulfonyl]-piperazine (II) of 1-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]- piperazine derivatives have been synthesized and the structures were confirmed by single crystal X-ray diffraction studies. The computational density functional theory (DFT) calculations have been carried out to shed light on reactive sites for electrophilic and nucleophilic nature of the molecules. Both the compounds were crystallized in the monoclinic crystal system, in P21/n space group wherein the piperazine ring in both the structures adopts a chair conformation. Both the compounds I and II exhibit intermolecular hydrogen bonds of the type C—H…O and contribute to the crystal packing. Further, the molecular Hirshfeld surface analysis was carried out which reveals the nature of intermolecular contacts, the fingerprint plot provides the information about the percentage contribution and revealed that the H…H (54.7% for compound I and 40.2% for compound II) interactions has the major contribution.