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Query: UMLS:C0432222 (SEM)
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A water-soluble isothiouronium-attached polythiophene (1(poly)) is prepared for the first time by the oxidative polymerization of 3-(3-(N-(2-methoxyethoxy)ethyl-N-methyl-S-isothiouronio)propoxy-4-methylthiophene (1) with FeCl(3). The gel-permeation chromatography analysis allows us to estimate the number average molecular weight (M(n)) and the polydispersity index (PDI) to be 5.68x10(5) and 1.4, respectively. The polymers (excited at 438 nm) show an absorption band at 438 nm and fluorescence at 546 nm, with 1.2 % fluorescence quantum yield when fluorescein was used as a reference. The pH-dependent absorption spectra at varying pH, indicates that aggregation starts at neutral conditions. At pH 5.5, 1(poly) exhibits a significant quenching in the fluorescence upon the addition of phytate (IP(6)), as a plausible analyte. This response is higher than that in the case of other anions such as adenosine 5-triphosphate (ATP), pyrophosphate (PPi), cis,cis-1,3,5-cyclohexanetriol triphosphate (CTP(3)), and H(2)PO(4)(-). As inferred from the SEM measurement, the phytate-induced spectral change has been explained on the basis of the pi-stacked aggregation of the polymer.
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PMID:Fluorescence sensing of phytate in water using an isothiouronium-attached polythiophene. 2009

Metal contamination of water is a serious challenge faced by environmental chemists, but there is also economic value in the removal of metals for recycling or extraction. Our prior observation that hydroxyfullerenes [C60O(x)(OH)y](n-) act as chelate agents to Fe(3+) suggests that these material, or derivatives, may be used for co-precipitation. We report the removal of main group (Al(3+), Ag(+), Ca(2+), and Zn(2+)) as well transition metal (Fe(3+), Co(2+), Cu(2+), Mn(2+), and Ni(2+)) and lanthanide (La(3+) and Nd(3+)) ions from solution. The resulting complexes have been characterized by XPS, SEM, TEM, and DLS. The competitive binding with Fe(3+) shows that the binding affinity with hydroxyfullerenes follows the order: Zn(2+) > Co(2+) > Mn(2+) > Ni(2+) > La(3+) > Nd(3+) > Cd(2+) > Cu(2+) > Ag(+) > Ca(2+) > Fe(3+) > Al(3+). The relative binding ability is dependent on ionic radius; however, divergent trends are observed for M(2+) and M(3+), i.e., for divalent ions the binding is stronger for smaller ions, while the opposite trend is observed for trivalent ions. Previously the coordination of hydroxyfullerene to metals was assumed to be analogous to a 1,2-diol or catechol. However, while ab initio calculations using [M(catecholate)n](n-) (n = 2, 3) provide an explanation of the observed trend for M(2+), the use of cis-cis-1,3,5-cyclohexanetriol and cis-1,3-cyclohexanediol as model ligands provides insight into the relative binding efficiency for M(3+).
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PMID:Understanding the relative binding ability of hydroxyfullerene to divalent and trivalent metals. 2564 89