Deo Nandan Kumar

Spectral studies on copper(II) complexes of biologically active glutathione

Copper(II) complexes of reduced glutathione (GSH) of general composition Na[Cu(L)(X)]*nH2O (where LH2=GSH; X=Cl-, NO3-, NCS-, CH3CO2-, HCO2-, ClO4- and n=0-4) have been prepared and characterized by elemental analysis, magnetic susceptibility measurements, IR spectroscopy, EPR spectroscopy and ligand-field spectroscopy. The EPR and ligand field spectra in the solid state suggest planar geometry for all the complexes.

Spectroscopic and thermal investigations of Cu(II), Zn(II), Cd(II), Pb(II) and Al(III) caproates

Five complexes: Cu(cap)2·4H2O, Zn(cap)2, Cd(cap)2·4H2O, Pb(cap)2 and Al(cap)3·4H2O (where cap is the caproate anion = CH3(CH2)4COO−) were synthesized and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis (TG), differential thermal analysis (DTA), UV-Vis spectra, 1H NMR and X-ray powder diffraction (XRD). Using the non-isothermal, Horowitz-Metzger (HM) and Coats-Redfern methods, the kinetic parameters for the non-isothermal degradation of the complexes were calculated using TG data. The infrared and 1H NMR data are in agreement with coordination through carboxylate, with cap acting as a bridging bidentate ligand. Thermogravimetric analysis of the hydrated complexes shows that the first degradation step is release of water molecules followed by decomposition of the anhydrous complexes, with release of caproate molecules.

Cobalt(II) complexes of new biomimetic polydentate amide ligands. A spectroscopic, thermal and potentiometric study

Complexes of CoII with N,N′-bis-(3-carboxy-1-oxopropanyl)-1,2-ethylenediamine(L1), N,N′-bis-(3-carboxy-1-oxopropanyl)-1,2-phenylenediamine(L2), N,N′-bis-(2-carboxy-1-oxophenelenyl)-1,2-phenylenediamine(L3) and N,N′-bis-(3-carboxy-1-oxoprop-2-enyl)-1,2-phenylenediamine(L4) have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, electronic spectra and thermal studies. Stability constants of the complexes have been evaluated potentiometrically. Vibrational spectra indicate coordination of amide and carboxylate oxygens of the ligands along with two water molecules giving a MO6 weak field octahedral chromophore. Electronic spectra support octahedral geometry around CoII. The [Co(L1)-(H2O)2] · 2H2O complex has the maximum activation energy and [Co(L3)(H2O)2] complex has the minimum activation energy. The order of stability constants of the CoII complexes with various ligands is due to their σ-donor abilities.

Spectral and thermal studies of alloxan complexes

The complexes of alloxan with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) Cd(II), Hg(II), Ti(IV) and Zr(II) have been isolated and characterized on the basis of elemental analysis, molar conductivity, spectral studies (mid infrared, 1H-NMR and UV/vis spectra), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The thermal decomposition of the metal complexes was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The kinetic thermodynamic parameters, E*, ΔH*, ΔS* and ΔG*, were calculated using Coats and Redfern and Horowitz and Metzger equations. The ligand and its complexes have been studied for possible biological activity including antibacterial and antifungal activity.