Synthesis, Characterization and Study of Thermal, Magnetic and Electrical Properties of Transition Metals Complexes of Some Newly Synthesized 2, 5-Substituted Oxadiazoles

Abstract

This paper reports the synthesis and characterization of transition metal complexes of newly synthesized 2,5-substituted-1,3,4-oxadiazoles with Cu(II), VO(IV), Ni(II), Zn(II) and Cd(II). The characterization of complexes were done by elemental analysis, UV-Vis, IR, ESR methods as well as the electrical conductance, magnetic susceptibility and thermal studies. The thermal behaviour provided confirmation of the complex composition as well as the number and the nature of water molecules and the intervals of thermal stability. The in vitro qualitative and quantitative antimicrobial activity assay of all the complexes was carried out.

DFT and TD-DFT Study of Bis[2-(5-Amino-[1,3,4]-Oxadiazol-2-yl) Phenol](Diaqua)M(II) Complexes [M = Cu, Ni and Zn]: Electronic Structures, Properties and Analyses

“…The frequency for this vibrational mode reported in [5] for the ligand 2-(5-mercapto-[1,3,4]-oxadiazol-2-yl)phenol which differs from AOYP only by the replacement of NH 2 (amino group) with SH (mercapto group), is 3219 cm −1 . The calculated frequency for the phenolic O-H stretching vibration is 3237 cm −1 , which is closer to the experimental value reported in [5] than that reported in [3]. The calculated frequency disagrees with the experimental value reported in [3] with a relative error of −4.28%.…”

“…The calculated frequency for the phenolic O-H stretching vibration is 3237 cm −1 , which is closer to the experimental value reported in [5] than that reported in [3]. The calculated frequency disagrees with the experimental value reported in [3] with a relative error of −4.28%. Equation (1) was used to calculate this relative error [25].…”

“…A comparison of the scaled wavenumbers calculated by the B3LYP/GEN method with experimental values reveals a very good agreement; with correlation coefficients of 0.985 and 0.992 for AOYP and its transition metal complexes respectively. The experimental IR frequency assigned to the phenolic O-H vibrational mode of AOYP is 3382 cm −1 , according to [3]. The frequency for this vibrational mode reported in [5] for the ligand 2-(5-mercapto-[1,3,4]-oxadiazol-2-yl)phenol which differs from AOYP only by the replacement of NH 2 (amino group) with SH (mercapto group), is 3219 cm −1 .…”

“…The IR frequencies of AOYP were calculated at the B3LYP/6-31G(d) level of theory while those of its complexes were calculated at B3LYP/GEN level. The corresponding experimental frequencies (also listed in Table 2) were obtained from [3] and [5]. The calculated frequencies are slightly higher than the observed values for the majority of the normal Table 2.…”

“…In the search for novel antimicrobial agents based on a backbone of oxadiazoles, researchers have in the recent years synthesized, characterized and studied the antimicrobial properties of a variety of complexes with 1,3,4-oxdiazole ligands. In 2013, Wanale and co-workers synthesized and characterized complexes of 2-(5amino- [1,3,4]-oxadiazol-2-yl)phenol with Cu(II), VO(IV), Ni(II), Zn(II) and Cd(II), but did not determine their geometrical parameters (bond lengths, bond angles and dihedral angles). These parameters can be conveniently determined theoretically, by quantum chemical calculations.…”