Zirconium(II) and palladium(II) mixed ligand metal complexes were synthesized by using an equimolar mixture of tetracycline (Tc) as primary ligand and salicylaldehyde as secondary ligand. The metal complexes were characterized by physico-chemical and spectroscopic techniques like CHN analysis, surface tension, pH, conductivity and melting point measurements. The spectroscopic characterization technique includes IR, (1H & 13C) NMR, UV/visible and Mass spectrometry methods. The SEM technique determines the surface morphology of the complexes. The thermal and kinetic stability of the complexes was obtained from TGA/DTA curves from which the parameters like E*, ΔH*, ΔS* and ΔG* have been calculated by using the Coats-Redfern equation. Molecular modeling gives a geometry of the complex which was obtained from Chem 3D Pro. 12.0 software program. The metal complexes of Zr-TcSal and Pd-TcSal have coordinated with tetrahedral and square planar geometry, respectively. The antibacterial susceptibility study of the synthesized metal complexes was done by Kirby-Bauer paper disc diffusion techniques on S. aureus, E. coli and P. aeruginosa clinical pathogens

A new series of mixed ligand complexes of Cd(II) and Mo(V) were successfully synthesized by refluxing the mixture solution of oxytetracycline hydrochloride (OTC.HCl) with an aqueous and alcoholic solution of metal (M = Cd(II) and Mo(V)) salts and an alcoholic solution of salicylaldehyde (Sal). The complexes were characterized by modern analytical and spectral methods such as elemental microanalysis, pH, conductivity, surface tension, viscosity, melting point, and spectral methods such as FT-IR, NMR, electronic absorption, SEM, and mass spectrometry. Conductivity measurements of the complexes revealed their electrolytic nature. The kinetic and thermal stabilities were investigated using thermogravimetric and differential thermal analysis techniques. Thermodynamic and kinetic parameters such as E∗, ΔH∗, ΔS∗, and ΔG∗ were calculated from TG curves using the Coats–Redfern method. Geometry optimization of the proposed structure of the complexes was achieved by running MM2 calculations in a Gaussian-supported CS ChemOffice 3D Pro.12.0 version software. The final optimized geometrical energies for respective Cd-OTC/Sal and Mo-OTC/Sal complexes were found to be 923.1740 and 899.3184 kcal/mol. The electronic absorption spectral study revealed a tetrahedral geometry for the Cd-OTC/Sal complex and octahedral geometry for the Mo-OTC/Sal complex. The antibacterial sensitivity of the complexes was evaluated against three bacterial pathogens such as S. aureus, E. coli, and P. mirabilis using the modified Kirby–Bauer paper disc diffusion method. The antibacterial study revealed significant growth inhibitory action of the complexes.

The two new novel heteroleptic complexes of the type [M(II)L1.L2] (M= Zr(II) & Pd(II), L1= oxytetracycline (Otc), and L2=salicylaldehyde (Sal)) have been synthesized and analyzed by physical measurements such as CHN, pH, and conductivity. The conductivity data revealed the electrolytic nature of Pd(II)Otc/Sal and the non-electrolytic nature of the Zr(II)Otc/Sal metal complex of mixed ligand. The structural characterizations of the metal complex were approved by spectroscopic analysis methods, such as IR, 1H & 13C-NMR, UV/ Visible, and ESI-MS studies. Thermal analysis (TGA/DTA) determines the thermal and kinetic stabilities of the metal complexes using a popular Coats-Redfern equation through which the activation parameters can be calculated easily. SEM can determine the surface morphology of metal complexes. The selected bond lengths, bond angles, final optimized energy, and geometry of complexes were obtained by running an optimization task in the 3D molecular modeling software program via Chem 3D Pro. 12.0.2. The final geometrical energy was found to be 921.7712 for Zr(II)Otc/Sal and 914.6006 Kcal/mol for Pd(II)Otc/Sal complexes. Based on the above study, Zr(II)Otc/Sal complex has tetrahedral geometry and the Pd(II)Otc/Sal complex has square planar geometry. The complexes were tested in vitro for antibacterial susceptibility study against various strains of clinical pathogenic bacteria such as Staphylococcus aureus (Gram-positive), Proteus mirabilis, and Escherichia coli (Gram-negative). For the antibacterial study, the Kirby-Bauer paper disc diffusion technique is applied by using 50, 25, and 12.5 μg/μL concentrations of the metal complex. Good antibacterial sensitivity was found against all tested pathogens in all synthesized complexes.

Diperiodatocuprate [DPC (III)] was selected to predict the kinetic studies for carbenicillin (CRBC) oxidation in the basic media. The investigation was completed in the presence of CoCl3 as a catalyst by using a UV/Visible spectrophotometer at 298K temperature and 0.01 mol-dm-3 ionic strength confirming a 1:4 stoichiometry between CRBC and DPC (III). Both spectral and elemental analysis was used to identify the final products. Monoperiodatocuperate [MPC (III)] was found to be the primary active species of DPC (III). Pseudo-first order reaction was declared for DPC (III), while fractional order reactions were noticed in the case of CRBC (substrate), Co (III) catalyst as well as KOH (alkali). However, the reaction was determined to be in negative fractional order for periodate. Spectral evidence, determination of various rate constants, and both activation, as well as thermodynamic parameters, were used to predict plausible mechanisms.

Synthesis and ab initio Determination of Bi 1.25 V 0.123 Ca 0.245 N 1.24 O 8 cubic structure via powder X-ray diffraction data