De bezonken actualiteit van een nieuwe wereldatlas

Contains fulltext : 179868.pdf (publisher's version ) (Open Access)14 december 199

Transition metal saccharide chemistry and biology: syntheses, characterization, solution stability and putative bio-relevant studies of iron-saccharide complexes

A number of Fe(III) complexes of saccharides and their derivatives, and those of ascorbic acid were synthesized, and characterized by a variety of analytical, spectral (FT-IR, UV-Vis, EPR, Mossbauer and EXAFS), magnetic and electrochemical techniques. Results obtained from various methods have shown good correlations. Data obtained from EPR, magnetic susceptibility and EXAFS techniques could be fitted well with the mono-, di- and trinuclear nature of the complexes. The solution stability of these complexes has been established using UV-Vis absorption and cyclic voltammetric techniques as a function of pH of the solution. Mixed valent, Fe(II,III) ascorbate complexes have also been synthesized and characterized. Reductive release of Fe(II) from the complexes using sodium dithionite has been addressed. In vitro absorption of Fe(III)-glucose complex has been studied using everted sacs of rat intestines and the results have been compared with that of simple ferric chloride. Fe(III)-saccharide complexes have shown regular protein synthesis even in hemin-deficient rabbit reticulocyte lysate indicating that these complexes play a role that is equivalent to that played by hemin in order to restore the normal synthesis of protein. These complexes have exhibited enhanced DNA cleavage properties in the presence of hydrogen peroxide with pUC-18 DNA plasmid

Synthesis, characterization and structure of Ti(IV) complexes of hydroxy-rich ligands

284-289<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Coordination chemistry of two multi-hydroxy rich ligands has been explored with Ti(IV) by isolating the resultant products followed by their characterization. One of the products is also structurally characterized by single crystal XRD.</span

Formation of mono- and di-amide-calix[4]arene derivatives from the reaction of <i>p-tert</i>-butyl-calix[4]arene and <img src='/image/spc_char/alpha.gif' border=0>-chloro-<i>N</i>,<i>N</i>-diethylacetamide in the presence of sodium hydride

549-552The formation of mono- and di (1,2 and 1,3)-amide derivatives of p-tert-butylcalix[4]arene in the presence of sodium hydride has been demonstrated.  All the compounds have been purified and characterized by various spectral methods.  Both 1H and 13C NMR spectra exhibit clear-cut differences between the 1,2-di- and 1,3-di-amide derivatives.

Role of saccharides in reduction and complexation of transition metal ions and the effect of zinc saccharides on some haematological variables

This article does not have an abstract

Saccharide complexes of lanthanides

227-239The main focus of this review article is to bring out different aspects of interactions of saccharides with lanthanide ions. various characteristic properties of lanthanide-saccharide complexes have been compared appropriately with those of the transition metal ones

Oxo-metal complexes of alkoxo rich ligands and reactivity of vanadium complexes

Oxo-metal centers, such as, VO3+, cis-VO+2 , cis-MoO22+ andtrans-UO22+ exhibited different coordination geometries and charge types to result in totally nine different types of structures, all of which were characterized by single crystal X-ray diffraction. Aqueous stability, reactivity towards acid, H2O2 and bromide of vanadium complexes are studied using absorption and 51V NMR spectra. Catalytic nature of the bromination reaction by vanadium complexes has also been addressed

Synthesis, characterization and structure of Ti(IV) complexes of hydroxy-rich ligands

Coordination chemistry of two multi-hydroxy rich ligands has been explored with Ti(IV) by isolating the resultant products followed by their characterization. One of the products is also structurally characterized by single crystal XRD

Formation of mono- and di-amide-calix[4]arene derivatives from the reaction of p-tert-butyl-calix[4]arene and α-chloro-N,N-diethylacetamide in the presence of sodium hydride

The formation of mono- and di (1,2 and 1,3)-amide derivatives of p-tert-butylcalix[4]arene in the presence of sodium hydride has been demonstrated. All the compounds have been purified and characterized by various spectral methods. Both 1H and 13C NMR spectra exhibit clear-cut differences between the 1,2-di- and 1,3-di-amide derivatives

Photo-physical behavior as chemosensor properties of anthracene-anchored 1,3-di-derivatives of lower rim calix[4]arene towards divalent transition metal ions

Anthracene anchored 1,3-di-derivatives of lower rim p-tert-butyl-calix[4]arene were synthesized and characterized. These derivatives were subjected to the binding studies with the divalent metal ions, viz., Mg2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ using fluorescence and absorption spectra. The imine moiety that is in conjugation with the anthryl unit is responsible for quenching the fluorescence in the absence of metal ion, however, in the presence of Fe2+ and Cu2+, the spectra showed very high enhancement in fluorescence intensity indicating that the lone pair present on the imine-N is involved in the metal ion binding and as a result the photo-induced electron transfer is prevented. Based on the photo-physical studies, it has been found that the anthracene derivative that is coupled with the calix[4]arene unit through an imine bond acts as a chemosensor for Fe2+ and Cu2+. The fluorescence studies are further augmented by the absorption spectra.© Elsevie