N2O2-complexes of oxovanadium(IV) with 2,2′-dihydroxybenzophenone thiosemicarbazones: Synthesis, EPR and electrochemical studies

Synthesis, molecular modelling, FT-IR, Raman and NMR characterization, molecular docking and ADMET study of new nickel(II) complex with an N4-tetradentate thiosemicarbazone

A new nickel(II) complex was synthesized by using S-propyl-thiosemicarbazide and 2-amino-3,5-dibromobenzaldehyde. The complex, obtained by the template effect of nickel ions, was structurally analysed by experimental and theoretical vibrational spectroscopy, NMR and density functional theory (DFT) calculations. By using DFT/B3LYP method with 6-311++G(d, p) basis set, the most stable molecular structure of the title molecule was calculated. The fundamental vibrational wavenumbers, IR and Raman intensities for the optimized structure of the molecule under investigation were determined and compared with the experimental vibrational spectra. The vibrational assignment was achieved using the calculated potential energy distributions of the vibrational modes. Moreover, the molecular electrostatic potential (MEP), the highest occupied molecular orbital (HOMO) and the lowest occupied molecular orbital (LUMO) energies were calculated, Molecular docking of the molecule was carried out against DNA in order to identify the potential inhibitory action of the title compound. The findings suggested that the aforementioned compound has a strong binding affinity to interact with DNA residues DT8, DC9, DG12, DG16, DA17, and DA18 through the intermolecular hydrogen bonds. Also the performed in silico ADMET analysis was the prediction of the synthesized molecule's pharmacokinetic and toxicity profile expressing good oral drug like actions and non-toxic nature. The complex has been shown to have the possibility to become a model molecule for drug development processes.Communicated by Ramaswamy H. Sarma.

Oxovanadium(IV) and Nickel(II) complexes obtained from 2,2'-dihydroxybenzophenone-S-methyl-thiosemicarbazone: Synthesis, characterization, electrochemistry, and antioxidant capability

2,2'-Dihydroxybenzophenone-S-methyl-thiosemicarbazone and 3-methoxy-salicylaldehyde were reacted in the presence of oxovanadium(IV) or nickel(II) ions to yield the N2O2-type-chelate complex. The synthesized complexes were characterized by employing elemental analysis, electronic and infrared spectra, 1H NMR spectra, magnetic measurements, and thermogravimetric analyses. The expected structures of oxovanadium(IV) and nickel(II) complexes were confirmed by using the single-crystal X-ray diffraction method. The presence of π-π stacked dimeric structures provided stronger crystalline formations. The optimized geometries and vibrational frequencies of the compounds were obtained using the DFT/ωB97XD method with the 6-31G (d,p) basis set and compared with the experimental data. The electrochemical characterization of the oxovanadium(IV) and nickel(II) complexes were carried out by using the cyclic voltammetry (CV) method. The oxovanadium(IV) complex gives a ligand-centered oxidation and a metal-centered one electron reduction and oxidation peaks corresponding to the VIV/IIIO and VIV/VO, respectively. The nickel(II) complex gives a ligand-centered oxidation and metal-centered (NiII/I) reduction peaks in a dimethyl sulfoxide (DMSO) solution. The redox potentials were calculated in terms of Gibbs free energy change of the redox reaction at the theory level of M06-L/LANL2DZ/PCM. In addition, the energy gap, HOMO and LUMO distributions were calculated. The total antioxidant capacities of the compounds were determined by using cupric reducing antioxidant capacity (CUPRAC) method, in which the oxovanadium(IV) complex was found to be powerful as an antioxidant agent.

Cu(ii) salen and 1,2,4-triazole complexes from thiosemicarbazone: synthesis, physicochemical and structural properties and cytotoxic activities

The complexes were synthesized from reaction of salicylaldehydethiosemicarbazone and ethylenediamine in the presence of CuCl₂.

Metal complexes of a pentadentate N2O3bis(semicarbazone) Schiff-base. A case study of structure-spectroscopy correlation

Schiff condensation of 2,6-diformyl 4-methylphenol with semicarbazide hydrochloride in 1:2 molar ratio produces the bis(semicarbazone) ligand, herein called H3L. A comprehensive spectroscopic analysis of the compound was performed by (1)H and (13)C NMR, FTIR and electronic spectroscopies. Assignments to the UV-vis spectrum of H3L were supported by semi-empirical quantum mechanics ZINDO/S calculations. The ligand H3L forms monoclinic crystals in the space group P21/c and its structure is stabilized by classic hydrogen bonds with propanone molecules. It promptly reacts with first row metal ions to produce the following coordination compounds: [Co2(L)(μ-NO3)]·DMF, [Ni2(H2L)(μ-CH3COO)(CH3COO)2]·2H2O, [Cu2(L)(μ-NO3)(H2O)2]·H2O, [Cu2(L)(μ-CH3COO)(H2O)2]·H2O and [Cu2(H2L)(μ-Cl)Cl2]·3H2O, that have different compositions, depending on the degree of deprotonation of the ligand upon coordination. Electronic and EPR spectroscopies as well as effective magnetic moment measurements of the complexes were used in an attempt to better understand their mode of coordination, the microsymmetry around the metal ions and magnetic properties.