A study on the hydroxylation of 20-membered hexaaza macrocyclic bicopper complexes

A study was made on the hydroxylation of six macrocyclic bicopper complexes with bridge of SCN^?, Cl^?, Br^?, I^?, N₃^? or OH^? respectively in aqueous solution. Electronic spectra and data of titration by ion selective electrode show that the basic structure of the complexes remained unchanged during hydroxylation and hydroxyl group bound to copper atom only at the axial direction of the complexes. pH titration was made by auto-titration and data acquisition system controlled by microcomputer. Data of pH titration was pq-analysed by program LEMIT which show that 1-4 hydroxyl groups bind to copper atom stepwisely. Twenty four stepwise hydroxylation constants of the complexes were calculated and concentration distribution of various species during pH changing and hydroxylation were obtained. The six complexes except that with bridge N₃^? formed dihydroxo-complexes mainly at about pH 9 and formed monohydroxo-complexes mainly at about pH 7.5.     

A study on bovine erythrocyte superoxide dismutase by controlled potential electrolysis and Raman spectra

The electrochemical behavior of Cu(2)Zn(2)SOD on mercury electrodes was studied by controlled potential electrolysis. By comparison of UV, Raman spectra and activity of Cu(2)Zn(2)SOD before electrochemical reduction and after re-oxidation, it is proved that the conformation and activity are not changed.     

Non-template synthesis and electrospray mass spectrometric study of some lanthanide(III) complexes

A new cryptand H₃L was synthesized by the direct condensation of tris(2-aminoethyl)amine (tren) with 2,6-diformyl-4-methoxyphenol (dmp) in the absence of a template ion. The complexes [M(H₃L)(NO₃)](NO₃)₂·xH₂O·yMeOH (M=Y, Sm, Nd; x=1–3, y=1,2) were characterized by several physical methods. The behaviours of the ligand and Nd(III) complex were investigated by electrospray mass spectrometry. The Nd(III) cryptate exhibits high thermodynamic and kinetic stability in solution for no cryptate fragmentation peaks were observed. A complex peak formed by the overlap of two species is also observed. The isotopic distributions of peak clusters in the mass spectrum of the Nd(III) cryptate were calculated.     

A study on oxygen insertion in dinuclear silver cryptates

Two novel silver(I) cryptates are reported in this paper. [Ag(2)(L(1)O)](ClO(4))(2).H(2)O and [Ag(2)L(1)](ClO(4))(2).1.5H(2)O were synthesized by the condensation of tris (3-aminopropyl) amine with m-phthalaldehyde in the presence of silver(i) ion, under aerobic and anaerobic conditions, respectively. (The ligand L(1)O represents the oxygen insertion product of L(1).) Cryptates 1, 2 and their hydrogenated ligand H(12)(L(1)O) 3 and H(12)L(1) 4 (obtained by reduction of the cryptates) were investigated by electrospray mass spectroscopy (ES-MS). 1 and 2 were also decomposed by HCl treatment and their products were separated and identified by HPLC and ES-MS. Our experiments show that cryptate 2 is able to activate dioxygen that results in quantitative aliphatic hydroxylation of L(1) on one of its HC=N bonds. Crystal structure analysis shows an interesting difference between 1 and 2 in that 1 is an oxygenated and 2 is a non-oxygenated cryptate. Up to date, ligand hydroxylation has not been achieved in silver(I) complex-O(2) systems.     

Incorporation of triazacyclononane into the metal phosphonate backbones

This paper reports the syntheses and crystal structures of a manganese and a uranyl phosphonate based on 1,4,7-triazacyclononane-1,4,7-triyl-tris(methylenephosphonic acid), namely, Mn3{C9N3H18(PO3)3}(H2O)6 x 1.5 H2O (1) and UO2{C9N3H19(PO3H)3} x H2O (2). Compound 1 shows a unique layer structure where the hydrophobic triazacyclononane moieties all reside on one side of the inorganic backbone of the manganese phosphonate layer while the hydrophilic coordinated water molecules reside on the other side. In compound 2, the triazacyclononane moieties are immobilized on the inorganic backbone of the uranyl phosphonate chains. The magnetic properties of compound 1 and the ion exchange properties of compound 2 have been studied.     

LixZryOz三元化合物的制备及表征

采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1～10μm间,BET分析表明样品比表面积处于1.0～9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.