Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacit...Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacity and good selectivity for urea.The sorption capacity was influenced by the metal content in the complex,time of sorption,concentration of urea etc.The sorption capacities were 83.6,79.1,72.9,69.4 and 53.4 mg/g for urea by the chitosan metal complexes of Cu(Ⅱ),Cd(Ⅱ),Co(Ⅱ),Zn(Ⅱ) and Fe(Ⅲ),respectively at pH 6.0 and the concentration of urea being 1 300 mg/L.展开更多
EPR spectra of three new quaternary gadolinium complexes(I： [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ： [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ： [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powder...EPR spectra of three new quaternary gadolinium complexes(I： [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ： [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ： [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powders and solutions have been investigated at different temperatures and solvents.New behavior of EPR spectra of complexⅢ was first observed in polycrystalline powder at 77K and three types of EPR spectra for three complexes,symmetry resonance spectrum for the complexⅡ ,U spectrum for the complexⅢ ,and asymmetry resonance spectrum for the complex I.The relationship of EPR features between the crystal- field strength in the complexes and local symmetry around Gd(Ⅲ ) was discussed.The crystal- field parameters b20 and asymmetry parametersλ′ of the complexes I andⅢ were estimated.展开更多
文摘Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacity and good selectivity for urea.The sorption capacity was influenced by the metal content in the complex,time of sorption,concentration of urea etc.The sorption capacities were 83.6,79.1,72.9,69.4 and 53.4 mg/g for urea by the chitosan metal complexes of Cu(Ⅱ),Cd(Ⅱ),Co(Ⅱ),Zn(Ⅱ) and Fe(Ⅲ),respectively at pH 6.0 and the concentration of urea being 1 300 mg/L.
文摘EPR spectra of three new quaternary gadolinium complexes(I： [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ： [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ： [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powders and solutions have been investigated at different temperatures and solvents.New behavior of EPR spectra of complexⅢ was first observed in polycrystalline powder at 77K and three types of EPR spectra for three complexes,symmetry resonance spectrum for the complexⅡ ,U spectrum for the complexⅢ ,and asymmetry resonance spectrum for the complex I.The relationship of EPR features between the crystal- field strength in the complexes and local symmetry around Gd(Ⅲ ) was discussed.The crystal- field parameters b20 and asymmetry parametersλ′ of the complexes I andⅢ were estimated.
