Infrared and Thermal Analysis of Vanadyl(II) Barbiturate Complex

An usual method for the preparation of vanadyl(II) barbiturate complex was performed under the chemical reaction of vanadyl(II) sulfate with barbituric acid (H2L) and formulated as: [VO(HL)2].2H2O. This new barbiturate complex was synthesis and characterized by elemental analysis, molar conductivity, magnetic measurements, infrared spectral method and simultaneous thermal analysis (TG/DTG) techniques. The molar conductance measurements proved that barbiturate vanadyl(II) complex is non-electrolytes. The infrared spectra of the barbituric and vanadyl(II) complex are used to identify the mode of coordination. Kinetic and thermodynamic parameters (E*, ΔH*, ΔS* and ΔG*) of H2L ligand and its complex are estimated according to the DTG curves.Â

Synthesis and spectroscopic characterizations of manganese(II), iron(III), copper(II) and zinc(II) hydrazine complexes as catalytic activity agents

ABSTRACT. This article deals with the preparation and coordination of NH2—NH2 hydrazine molecule compounds. The hydrazine sulfate complexes of Mn(II), Fe(III), Cu(II), and Zn(II) were prepared. These complexes were characterized by elemental, infrared, conduction, electron absorption spectroscopy, magnetic susceptibility, thermogravimetric analyses, X-ray powder diffraction (XRD) patterns and atomic force microscopy (AFM) studies. The magnetic measurements were confirmed that the Mn(II), Fe(III), Cu(II), and Zn(II) hydrazine complexes have an octahedral geometric structure. Thermogravimetric and its differential thermogravimetric analysis referred that all complexes passed through two-to-three thermal degradation steps with solid metal sulfate as a residual product. The infrared spectra inferred that the NH2—NH2 ligand forms complexes through nitrogen atoms of the—NH2 moiety, while the elemental analysis indicates [M(NH2—NH2)3]SO4 (where M = Mn(II), Cu(II), and Zn(II)) while the iron(III) complexes have the [Fe2(NH2—NH2)4(SO4)2]SO4 formula of coordination compounds, NH2—NH2 acts as a double bond. Both XRD and AFM analysis deduced that the synthesized hydrazine metal complexes were found to be in nano scale range 10—30 nm.                 KEY WORDS: Hydrazine, FTIR, AFM, XRD, Transition metals Bull. Chem. Soc. Ethiop. 2022, 36(1), 33-44.                                                                    DOI:   https://dx.doi.org/10.4314/bcse.v36i1.4                                                    &nbsp

Preparation, spectroscopic and thermal studies on the zinc(II), cadmium(II), tin(II), lead(II) and antimony(III) creatinine complexes

ABSTRACT. Zinc(II), cadmium(II), tin(II), lead(II) and antimony(III) complexes of creatinine with the composition of [M(creat)2Xn].xH2O, (X = Cl or NO3; n = 2-6) were prepared. The complexes were characterized by analytical and spectral methods. The analysis of FT-IR and Raman spectra helps to understand the coordination properties of the creatinine ligand and to determine the probable structure of the complexes. The shift in the resonances of cyclic NH proton in the 1H NMR when compared to the ligand indicated that cyclic nitrogen coordinates. Conductivity measurements in DMSO suggested that the complexes are non-electrolytes. Thermal decomposition behavior of the complexes was also discussed.   KEY WORDS: Creatinine, TGA/DTA, Metal complexation, Raman spectroscopy   Bull. Chem. Soc. Ethiop. 2022, 36(4), 831-842.                                                              DOI: https://dx.doi.org/10.4314/bcse.v36i4.

IR, 1H-NMR, UV-Vis and thermal studies on the Rhodamine 6G charge-transfer complexes

Charge-transfer (CT) complexes formed between Rhodamine 6G (Rh6G) as donor with iodine, CLA and PA as acceptors have been studied spectrophotometrically. The synthesis and characterization of Rhodamine 6G CT-complexes of iodine, [(Rh6G)2]I+.I3ˉ, chloranilic acid (CLA), [(Rh6G)(CLA)] and picric acid (PA) [(Rh6G)(PA)] were described. These complexes are readily prepared from the reaction of Rh6G with I2, CLA and PA with CHCl3 solvent. Mid and far IR, 1H-NMR, UV-Vis techniques, elemental analyses (CHN) and thermal studies, characterize the three new Rhodamine 6G charge-transfer complexes. Modified Benesi-Hildebrand method was applied to the determination of association constant and molar extinction coefficient.KEY WORDS: Rhodamine 6G, Charge transfer complexes, Picric acid, Chloranilic acid, Iodine, Thermal studies Bull. Chem. Soc. Ethiop. 2011, 25(1), 137-146

Four new tin(II), uranyl(II), vanadyl(II), and zirconyl(II) alloxan biomolecule complexes: synthesis, spectroscopic and thermal characterizations

ABSTRACT. The alloxan as a biomolecule ligand has been utilized to synthesize thermodynamically and kinetically stabilized four new tin(II), uranyl(II), vanadyl(II), and zirconyl(II) complexes. In the complexes, tin(II) ion present is in tetrahedral arrangement, zirconyl and vanadyl(II) ions present are in square pyramid feature but uranyl(II) ion present is in octahedral arrangement and all are coordinated by two bidentate alloxan ligand in complexes. The synthesized alloxan ligand coordinate with central metal(II) ion through oxygen in position C2=O and the nitrogen in position N1 developing a 4-membered chelate ring. Synthesized Sn(II), UO2(II), VO(II), and ZrO(II) complexes via bidentate ligand have been accurately described by various spectroscopic techniques like elemental analysis (C, H, N, metal), conductivity measurements, FT-IR, UV-Vis, 1H-NMR, and TGA. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS* and ΔG* were calculated using Coats and Redfern and Horowitz and Metzger equations.   KEY WORDS: Alloxan, Metal ions, Spectroscopy, Ligand, Coordination, Thermogravimetry   Bull. Chem. Soc. Ethiop. 2022, 36(2), 373-385.    DOI: https://dx.doi.org/10.4314/bcse.v36i2.11                                                          &nbsp

Biomarkers charge-transfer complexes of melamine with quinol and picric acid: Synthesis, spectroscopic, thermal, kinetic and biological studies

AbstractTwo new melamine (MA) charge transfer complexes with quinol and picric acid in aqua media have been synthesized and structurally characterized. The obtained complexes with the general formula [(MA)(acceptor)2] with a 2:1 acceptor:donor molar ratio. Elemental analysis (CHN), electronic spectra, photometric titration, mid infrared spectra, 1H NMR spectra and thermogravimetric analysis (TG) were used to predict the position of the charge transfer interaction between the donating and accepting sites. The MA CT-complexes were antimicrobial assessment against two kinds of bacterial and fungal species

Spectrophotometric and Thermal Studies of the Reaction of Iodine with Nickel(II) Acetylacetonate

The reaction of iodine (acceptor) and nickel(II) acetylacetonate (donor) was studied photometrically in different solvents such as chloroform, dichloromethane and carbon tetrachloride at room temperature. The results indicate the formation of a 1: 1 charge-transfer complex in each solvent and the iodine complex is formulated as the triiodide species [Ni(acac)2]2I+.I3-, based on the characteristic electronic absorptions of the I3- ion at 361 and 285 nm, as well as on the far infrared absorption bands characteristic of the I3- ion with C2v symmetry. These bands are observed at 132, 101 and 84 cm-1 and are assigned to na(I-I), ns(I-I) and d(I3-), respectively. The values of the equilibrium constant (K), absorptivity (e) and oscillator strength (f) of the iodine complex are shown to be strongly dependent on the type of solvent used. The important role played by the solvent is suggested to be mainly due to the interaction of the ionic complex with the solvent. The proposed structure of the new solid triiodide charge-transfer complex reported in this study is further supported by thermal and mid-infrared measurements. (South African Journal of Chemistry: 2003 56: 10-14

Novel Papaverine Metal Complexes with Potential Anticancer Activities

Cancer is one of the leading causes of death worldwide. Although several potential therapeutic agents have been developed to efficiently treat cancer, some side effects can occur simultaneously. Papaverine, a non-narcotic opium alkaloid, is a potential anticancer drug that showed selective antitumor activity in various tumor cells. Recent studies have demonstrated that metal complexes improve the biological activity of the parent bioactive ligands. Based on those facts, herein we describe the synthesis of novel papaverine–vanadium(III), ruthenium(III) and gold(III) metal complexes aiming at enhancing the biological activity of papaverine drug. The structures of the synthesized complexes were characterized by various spectroscopic methods (IR, UV–Vis, NMR, TGA, XRD, SEM). The anticancer activity of synthesized metal complexes was evaluated in vitro against two types of cancer cell lines: human breast cancer MCF-7 cells and hepatocellular carcinoma HepG-2 cells. The results revealed that papaverine-Au(III) complex, among the synthesized complexes, possess potential antimicrobial and anticancer activities. Interestingly, the anticancer activity of papaverine–Au(III) complex against the examined cancer cell lines was higher than that of the papaverine alone, which indicates that Au-metal complexation improved the anticancer activity of the parent drug. Additionally, the Au complex showed anticancer activity against the breast cancer MCF-7 cells better than that of cisplatin. The biocompatibility experiments showed that Au complex is less toxic than the papaverine drug alone with IC50 ≈ 111 µg/mL. These results indicate that papaverine–Au(III) complex is a promising anticancer complex-drug which would make it a suitable candidate for further in vivo investigations.Peer Reviewe

New chemical procedures for preparation of manganese(II), cobalt(II), zinc(II) and cadmium(II) carbonates under the catalytic behavior of metal ions: Discussion of infrared spectral bands

Abstract: Mn(II), Co(II), Zn(II) and Cd(II) carbonates, respectively, were achieved by a new chemical procedure under the reaction of aqueous solutions of metal ions (MnCl 2 , Co(NO 3 ) 2 , Zn(NO 3 ) 2 or CdCl 2 ), potassium iodide and urea with molar ratio 1:2:10, respectively, at ~ 90 o C for 3 hrs. The infrared spectra of the results indicate absence of the essential bands of urea, but existed of the characteristic bands of ionic carbonate, CO 3 2-. An important chemical mechanisms discussed the preparation of Mn(II), Co(II), Zn(II) and Cd(II) carbonate compounds were suggested

Synthesis, spectroscopic characterizations and DFT studies on the metal complexes of azathioprine immunosuppressive drug

ABSTRACT. A complex of the immunosuppressive drug azathioprine with Cr(II), Mn(II), Fe(II), Zn(II), Cu(II), Ni(II), and Co(II) were synthesized and characterized through spectroscopic and thermal studies. The infrared spectra show the coordination of azathioprine via N(9) to the metal, also, the range around 640–650 cm−1 remains unchanged in the complexes, indicating the possibility that the ether group may not be involved in the binding. Thermogravimetric analysis (TG), thermogravimetric derivational analysis (DTG), and differential thermogravimetric analysis (DTA) have been studied in the temperature range from 0 °C to 1000 °C. The study of pyrolysis showed that all complexes decompose in more than one step and that the final decomposition product is metal oxide. The DFT (density functional theory) with B3LYP/6-31G++ level of theory was used to study the optimized geometry, HOMO→LUMO energy gap, and molecular electrostatic potential map of azathioprine before and after deprotonation.                 KEY WORDS: Azathioprine, Spectral study, Thermal study, Decomposition products, DFT Bull. Chem. Soc. Ethiop. 2022, 36(1), 73-84.                                                                   DOI: https://dx.doi.org/10.4314/bcse.v36i1.