Heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes for efficient photocatalytic and biological applications

263-277We report the synthesis and characterization techniques of mononuclear, heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes. These heterocyclic derivatives, Schiff base (indal-2-abu), are obtained from the reaction between indole- 3-carboxaldehyde (indal) and 2-aminobutyric acid (2-abu). From the fundamental analysis, it has been found that the Schiff base with the aforementioned metal ions forms four coordinated mononuclear complexes on 1:2 (metal:ligand) stoichiometry. The structural changes of the complexes are analyzed by FT-IR, electronic and magnetic analysis. The photocatalytic dye degradation activity study of the compounds is performed under UV-light using methylene blue (MB) dye. All the complexes are found to be excellent catalysts for the degradation of MB. Molecular docking is used to recognize the energetic site of the receptor, and attain the finest geometry of the ligand-receptor complex. Furthermore, antimicrobial investigations of Schiff base and its complexes are tested and the results are discussed in detail

Heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes for efficient photocatalytic and biological applications

We report the synthesis and characterization techniques of mononuclear, heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes. These heterocyclic derivatives, Schiff base (indal-2-abu), are obtained from the reaction between indole-3-carboxaldehyde (indal) and 2-aminobutyric acid (2-abu). From the fundamental analysis, it has been found that the Schiff base with the aforementioned metal ions forms four coordinated mononuclear complexes on 1:2 (metal:ligand) stoichiometry. The structural changes of the complexes are analyzed by FT-IR, electronic and magnetic analysis. The photocatalytic dye degradation activity study of the compounds is performed under UV-light using methylene blue (MB) dye. All the complexes are found to be excellent catalysts for the degradation of MB. Molecular docking is used to recognize the energetic site of the receptor, and attain the finest geometry of the ligand-receptor complex. Furthermore, antimicrobial investigations of Schiff base and its complexes are tested and the results are discussed in detail

Synthesis, spectroscopic characterization, solid state d.c. electrical conductivity and biological studies of some lanthanide(III) chloride complexes with a heterocyclic Schiff base ligand

Condensation of 2-hydroxy-1-naphthaldehyde with 2-amino-3-carboxyethyl-4,5-dimethylthiophene in 1:1 molar ratio, yielded a potentially tridentate Schiff base viz. 2-[N-(2′-hydroxy-1-naphthylidene)amino]-3-carboxyethyl-4,5-dimethylthiophene (HNAT). This ligand formed complexes with lanthanum(III), cerium(III), praseodymium(III), neodymium(III), samarium(III), europium(III) and gadolinium(III) chloride under well defined conditions. These complexes were characterized through elemental analysis, molar conductance, magnetic moment measurements, IR, UV–Vis, FAB mass and 1H NMR spectral studies. Analytical data showed that all the metal complexes exhibited 1:1 metal–ligand ratio. Molar conductance values adequately confirmed the non-electrolytic nature of the metal complexes. The proton NMR spectral observations supplement the IR spectral assignments. The spectral data revealed that the ligand acted as neutral tridentate, coordinating to the metal ion through azomethine nitrogen, ester carbonyl and naphtholate oxygen without deprotonation. The ligand and its lanthanum(III) chloride complex were subjected to XRD studies. The lanthanum(III) chloride complex has undergone a facile transesterification reaction. The solid state d.c. electrical conductivity of some selected complexes were measured as a function of temperature, indicating the semiconducting nature of the metal complexes. The antimicrobial activities were examined by disk diffusion method against some pathogenic bacterial and fungal species

Synthesis, spectroscopic investigation and antimicrobial activities of some transition metal complexes of a [(2-hydroxyacetophenone)-3-isatin]-bishydrazone

A bishydrazone was obtained by the condensation of isatin monohydrazone with 2-hydroxyacetophenone, which formed a series of complexes with manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II). The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic moment, IR, UV–Visible, mass, 1H NMR, EPR, and thermal analysis. Spectral studies revealed that the ligand acted as monobasic tridentate, coordinating to the metal ion through the deprotonated phenolate oxygen, azomethine nitrogen and carbonyl oxygen atom of the isatin moiety. The low molar conductance values indicate that all complexes are non-electrolytes. Based on the spectral results and magnetic susceptibility measurements, suitable geometry was proposed for each complex. The EPR spectral data indicated that metal–ligand bond had considerable covalent character. The ligand and its nickel(II) complex were subjected to XRD studies. Thermal decomposition study of nickel(II) complex was also carried out. In vitro biological screening effects of the compounds were tested against the bacteria and the fungal species by the agar disc diffusion method. A comparative study of the MIC values of the ligand and its complexes indicated that the copper(II) complex exhibited higher antimicrobial activity than the free ligand. The corrosion inhibitory activity of the ligand and its nickel(II) complex used in acid (H2SO4) media was also examined by weight loss measurements

Investigation of Zn2TiO4 as fluorescence quenching probe for sensing of metal ions

In the present work, rutile-free Zn2TiO4 has been synthesized by the solid-state method using TiO2 as hydrated titania and ZnO of 1:2 molar ratio. The reaction mixture was calcined at different temperature ranges, 550 °C to 950 °C. The rutile-free, cubic spinel-type Zn2TiO4 powders were obtained at 950 °C and confirmed by Raman, FI-IR spectroscopy, and XRD results. SEM images showed that the particles are irregular micron-sized and highly aggregated. From the diffuse reflectance spectral studies, the optical bandgap of the calcined products was calculated and it was found to be in the range of 3.25 to 3.79 eV. An attempt was made to examine the metal ion sensing properties of the prepared Zn2TiO4, by monitoring their photoluminescence intensity via quenching effects upon adding various metal ions. The sensing abilities were also evaluated using the standard Stern–Volmer quenching model. The results showed that Zn2TiO4 possesses high sensitivity toward iron ions