Spectroscopic (IR, Raman, UV–Vis) study and thermal analysis of 3d-metal complexes with 4-imidazolecarboxylic acid

Abstract

In this work, the spectroscopic (IR, Raman, UV-Vis) and thermal properties of 3d metal complexes with 4-imidazolecarboxylic acid were studied in order to determine the effect of 3d metals [i.e., Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II)] on the electronic structure and physicochemical properties of the ligand. The spectroscopic studies showed that the 3d-transition metals stabilize the electronic system of 4-imidazolecarboxylic acid. Similar results were obtained previously for benzoic and pyridinecarboxylic acids. The complexes synthesized in an aqueous medium were hydrated, as determined by the elemental and thermogravimetric analysis. The complexes of 4-imidazolecarboxylic acid have the general formula: M(C 3 N 2 H 3 COO) x ÁnH 2 O where M = Mn, Fe, Co, Ni, Cu, Zn, x = 3 for iron complex, x = 2 for other complex and n = 0-3. Thermogravimetric analysis conducted in oxygen atmosphere showed that the complexes decompose to metal oxides. During the thermal decomposition process carbon monoxide, carbon dioxide and imidazole ring degradation products are released.

Synthesis, Spectroscopic, Calculated and Thermal Study of Copper and Cobalt Complexes with Dacarbazine

“…IR, NMR studies and literature X-ray data on the structure of dacarbazine complexes [36] showed that metals such as copper and cobalt coordinate the ligand (dacarbazine) through the carbonyl group and the nitrogen atom from the imidazole ring. A similar type of metalligand coordination has been observed for 3d-transition metal complexes with imidazole carboxylic acid [38]. On the basis of spectroscopic studies (IR, Raman) and theoretical calculations, it was found that 3d metals affect the electronic charge distribution of the aromatic ring of ligand.…”

“…The total electronic density of the C-ring of the copper complex is greater than that of the cobalt complex. Studies of 4imidazole carboxylic acid complexes with 3d-transition metals (including copper and cobalt) also showed that copper and cobalt had a stabilizing effect on the aromatic system of the imidazole ring [38].…”

Three cobalt-based coordination polymers with tripodal carboxylate and imidazole-containing ligands: syntheses, structures, properties and DFT studies

“…41 The presence of the characteristic bands at 1072 cm −1 for 1, 1018 cm −1 for 2, 1083 cm −1 for 3 suggest the v C–N stretching vibrations of the imidazole ring. 42 The absorptions about 650–880 cm −1 of 1–3 can be attributed to the v C–H bending vibrations of phenyl ring.…”

Enhancement of Gel Strength of Itaconic Acid-Based Superabsorbent Polymer Composites Using Oxidized Starch

“…In addition, the CSAP and SSAP exhibit peaks at 1584 cm −1 and 1386 cm −1 due to the carboxylate (COO − ) ion generated by neutralization of the carboxyl groups. Since carboxylate has a resonance structure, the C=O stretching vibrations are divided into symmetrical and asymmetrical peaks [ 27 ]. The band at 1690 cm −1 in the spectrum of OS is assigned to the stretching vibrations of the carbonyl groups due to oxidation of the starch molecule.…”