Synthesis, structural characterization, DFT, fluorescence, and redox behaviour of 4-[5-(2-picolylsulfanyl)-1,3,4-oxadiazole-2-yl]-pyridine

Abstract

The effective experimental content of this paper reports the synthesis of new 1,3,4-oxadiazole derivative 4-[5-(2-picolylsulfanyl)-1,3,4-oxadiazole-2-yl]-pyridine (pop) which was carried out in a cyclization reaction containing potassium N′-(pyridine-4-carbonyl)-hydrazinecarbodithioate in the presence of 2-picolyl chloride. The synthesized compound pop has been characterized by elemental analyses, UV–vis., Infrared, NMR, and X-ray diffraction data which crystallizes in a triclinic system having space group P-1. The dihedral angle formed between the pyridine ring and oxadiazole ring indicates that all the rings present in the compound are planar with each other. An electrochemical study shows that compound pop exhibits a reversible redox process assignable to a one-electron transfer reaction. The intermolecular C–H···N hydrogen bonding and π···π interactions provide stability to the structure of compound pop. The fingerprint plots associated with Hirshfeld surface analysis clearly shows that there are two types of weak interactions N···H–C and S···C through red spots. Fluorescence spectra of Co2+, Cr2+, Cu2+, Cd2+, Hg2+, and Zn2+ ions with pop exhibit better fluorescence whereas Mn2+ and Ni2+ ions are less fluorescent as compared to the free pop. To get a better understanding of Frontier molecular orbitals and intramolecular charge transfer property, theoretical calculations, such as density functional theory (DFT), were performed which indicates that compound pop is soft and highly reactive. © 2021