10 research outputs found
TRANSITION-METAL SACCHARIDE CHEMISTRY AND BIOLOGY - SYNTHESIS, CHARACTERIZATION, REDOX BEHAVIOR, BIOINTERACTION AND DATA CORRELATIONS OF DINUCLEAR CHROMIUM(III) COMPLEXES
A series of dinuclear chromium(III) complexes has been synthesised by reduction of chromate by a variety of saccharides and related compounds. The complexes have been characterised by various analytical (elemental and ICP-AES analysis, TLC, HPLC) and spectroscopic (UV/VIS, FTIR, EPR, H-1 and C-13 NMR) methods. Antiferromagnetic interactions between the two Cr-III centres have been established by magnetic susceptibility measurements and the hydrolytic stability and redox behaviour of the complexes have been established by extensive electrochemical studies which gave several correlations. The interaction of some of the complexes with DNA has been studied by gel electrophoresis
TRANSITION-METAL SACCHARIDE INTERACTIONS - SYNTHESIS AND CHARACTERIZATION OF VANADYL SACCHARIDES
Low molecular weight saccharide complexes of vanadium of the type [VO(sacch)(2)](2-), were synthesized for the first time by simple and reproducible methods in nonaqueous media. These reactions yielded water-soluble products which were characterized by various analytical and spectroscopic techniques and by cyclic voltammetry. The vanadyl D-glucose complex 1 shows a resemblance to a natural vanadium-binding component vanadobin, isolated from the tunicate Ascidia sydneiensis samea. All the saccharide complexes are stable in solution for long periods under ambient conditions without being oxidised and showed no hydrolysis in the pH range 2-12. All the saccharide complexes reported in this paper show evidence for the V(IV) species
TRANSITION-METAL SACCHARIDE CHEMISTRY - SYNTHESIS, SPECTROSCOPY, ELECTROCHEMISTRY AND MAGNETIC STUDIES OF CHROMIUM(III)-HEXOSE COMPLEXES AND THEIR IN-VITRO INTERACTION WITH DNA
Saccharide complexes of Cr(III) were synthesized via chromate reduction. Hexose monosaccharides such as D-glucose, D-fructose, D-galactoSe, D-mannose and L-sorbose and some acid derivatives, such as D-galacturonic acid and D-gluconic acid, were used. The final Cr(III) products were isolated, purified and characterized by various analytical, spectroscopic, magnetic and electrochemical methods. All the products reported here are shown to be dinuclear in nature. The inherent stability and robust nature of these complexes is demonstrated and they are shown to affect the pSV2neo plasmid (DNA) structure in gel electrophoretic experiments
IN-VITRO REDUCING ABILITIES TOWARDS CHROMATE OF VARIOUS HYDROXY-CONTAINING COMPOUNDS, INCLUDING SACCHARIDES AND THEIR DERIVATIVES
The reduction of potassium chromate has been carried out with a variety of OH-containing compounds as reductants, which include pentoses, polyols, glycols, and sugar derivatives. The corresponding reactions were followed using UV-vis and EPR spectroscopies and electrochemistry. The progress of the chromate reduction reactions has been monitored by measuring UV-vis and EPR spectra as a function of time. The observed pseudo first-order reaction rate constants are derived based on the changes in the intensities of the Cr(VI), Cr(V), and Cr(III) signals. Cyclic voltammograms of the simple reductants and their final Cr(III) products formed from the reactions of chromate have also been measured. The reductive abilities of all these reductants have been derived from the spectral data and are discussed on a comparative basis. Based on the results, the aspects that makes a particular reductant more efficient has been addressed. The results obtained from UV-vis, EPR, and cyclic voltammetry are found to be mutually dependent and exhibit among themselves a linear correlation, suggesting that both the reducing and complexing nature of these molecules play important roles in the chromate reduction
TRANSITION-METAL SACCHARIDE CHEMISTRY - SYNTHESIS AND CHARACTERIZATION OF SOME MONOSACCHARIDE COMPLEXES
Synthesis and characterization of mononuclear complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with D-fructose and dinuclear complexes of Cr(III) with D-glucose, D-fructose, and L-sorbose are reported. Cyclic voltammetric studies of these complexes suggest their robustness over a wide pH range. Cr(III)-saccharide complexes are found to affect the structure of pSV2 neo DNA irreversibly
Synthesis, characterization and DNA interaction studies of Cr-III products isolated from Cr-VI reduction with -SH containing molecules
Chromium(III)-containing products were isolated from the reduction of chromate using molecules possessing the thiol function, i.e. L-cysteine, L-cysteine-ethyl ester and mercaptopropanediol. The products were characterized by various analytical, spectroscopic, magnetic and electrochemical studies. The in vitro interaction of these products with pUC18DNA has shown alterations in the DNA structure as established using agarose gel electrophoresis