Cobalt(II) complexes of tetradentate Schiff bases of the type CoL [H2L=C20H16N2O2 (H2dsp), C21H18N2O2 (H2dst), C20H15N3O4 (H2ndsp) and C16H16N2O2 (H2salen)] have been synthesized and characterized by UV-visible, IR, and magnetic studies. Various thermodynamic parameters have been calculated for the decomposition step using TG/DTA. C20H14N2O2Co complex has the minimum and C16H14N2O2Co complex has the maximum activation energy.
of reduced glutathione (GSH) of general composition [Pb(L)(X)]H2O
(where L=GSH; X=Cl,
NO3, CH3COO, NCS) have been
synthesized and characterized by elemental analyses, infrared spectra and
electronic spectra. Thermogravimetric (TG) and differential thermal analytical
(DTA) studies have been carried out for these complexes. Infrared spectra
indicate deprotonation and coordination of cysteinyl sulphur with metal ion.
It indicates the presence of water molecule in the complexes that has been
supported by TG/DTA. The thermal behaviour of complexes shows that water molecule
is removed in first step-followed removal of anions and then decomposition
of the ligand molecule in the subsequent steps. Thermal decomposition of all
the complexes proceeds via first order kinetics. The thermodynamic activation
parameters, such as E*, A,
and ΔG* have been calculated. The
geometry of the metal complexes has been studied with the help of molecular
modeling for energy minimization calculation.
Authors:B. S. Garg, R. Dixit, A. L. Singh, and R. K. Sharma
Chromium(III) complexes of the type Cr(A)(A′)2, Cr(A)2(A′) and Cr(A)3 have been prepared (whereA is either piperidyldithiocarbamate or morpholyldithiocarbamate andA′ is glycine or oxine or acetylacetone moiety). The mixed ligand complexes have been charac terized by elemental analyses, magnetic susceptibility measurements and thermal studies. The complexes show magnetic moment in the range of 3.5–4.3 B.M. which corresponds to three unpaired electrons. TG studies have also been carried out, in order to study the mode of decomposition of the complexes and to evaluate various kinetic parameters.