Synthesis and Charactezation of Some New 1,3,4-Thiadiazole Compounds Derived from α-methyl Cinnamic Acid and their DFT Studies

Abstract

Some novel 1,3,4-thiadiazole compounds derived from α-methyl cinnamic acid was synthesized, in this study. The structures of these compounds were elucidated by using spectroscopic methods such as FT-IR spectroscopy, 1 H-NMR spectroscopy, 13 C-NMR spectroscopy. Then, the absorption characteristics of the compounds were also examined by using UV-Vis spectrophotometer. In addition, the geometrical and electronic properties as well as Ultraviolet Visible analyzes of the compounds were theoretically done by using the density functional theory. The electronic configurations of the compounds substituted fluoro, chloro and methoxy have been investigated and how to effect chemical reactivity parameters to this configuration have been analyzed by using frontier molecular orbital energies. The calculated values obtained by B3PW91 with 6-311++G basis set and B3LYP with cc-PVTZ basis set are in good agreement with the experimental data. The results show that the UV-Vis absorptions are noticeably influenced by the o-, m-or p-positions of Cl, F and methoxy substituents. The methoxy substituent has more effect on the LUMO energies when compared to the Cl and F substituents. Moreover, positions of the substituents in the isomeric compounds were found to influence the molecular electronegativity and absorption wavelength. The absorption wavelength has the greatest value as the electronegativity of the isomer structures in the p-position of the substituents is smaller.

New 1,3,4-thiadiazole compounds: synthesis, spectroscopic characterisation and theoretical analyses based on DFT calculations

“…In addition, the stretching vibrations of C=N, aromatic C-H, aliphatic C-H and aromatic C=C are respectively reported in the following ranges: 1689-1471, 3100-3000, 3000-2840 and 1650-1450 cm −1 . Moreover, the peaks belonging to the conjugated C=C and C-S-C are found at around 1645 and 700 cm −1 [1,2].…”

“…One of the most important compounds in this field, i.e., 1,3,4-thiadiazole derivatives, are five-membered heterocyclic compounds containing one sulfur and two nitrogen atoms [1]. These derivatives are used in a wide variety of fields such as the pharmaceutical industry, materials science and organic synthesis [2]. Recently, a great variety of 1,3,4-thiadiazoles, to which aromatic moieties with different substituents are attached, have been intensively investigated.…”

Synthesis, Electronic and Spectral Properties of New 1,3,4-Thiadiazole Compounds and the Spectral Analysis of Their Conformers Using Density Functional Theory

“…Heterocyclic systems containing nitrogen and sulphur atoms have recently become very attractive for therapeutics. 1,2 The molecules including the 1,3,4-thiadiazole moiety are used in many applications because they contain two heterocyclic aromatic moieties. Their different derivatives have been used as antimicrobials, 3 antifungal, 4 antibacterial, 5 antileishmanial, 6 analgesic, antidepressant, 7,8 etc. In this study, 5-[3-phenylypropyl]-N-[2′-methoxycarbonylphenyl]-1,3,4-thiadiazol-2-amine (Compound I) and 5-(1-methyl-2phenylethenyl)-N-[2′-methoxycarbonylphenyl]-1,3,4-thiadiazol-2amine (Compound II) were synthesized, and the conformal structures of these compounds were investigated theoretically.…”