In situ ESR and UV/vis spectroelectrochemical study of eosin Y upon reduction with and without Zn(II) ions.

The electroreduction of eosin Y on a platinum electrode in deaerated slightly acidic aqueous 0.1 mol L(-1) potassium chloride medium is followed in situ by electron spin resonance (ESR) spectroscopy and UV/Vis spectroscopy. The electrochemical formation of a semiquinone radical is proved by both the appearance of an absorbing band at 408 nm, and a strong ESR signal observed during a negative-going scan. The system is also studied in the presence of Zn(II) ions due to its importance for understanding the growth mechanism of nanostructured ZnO/Eosin Y hybrid films by electrodeposition; under such conditions the ESR and UV/Vis response of the semiquinone radical is not observed. Zinc (II) ions form a complex with the dye, which is reduced by a fast two-electron process.     

油漆工头发中铁、锌、铜水平的研究

对８２名苯作业工人和１００名对照组工人的发铁、发锌和发铜含量水平进行了研究。结果揭示，油漆作业工人发铁含量为１０．３×１０－６±２．３×１０－６，明显低于对照组（１４．４×１０－６±３．１×１０－６）．Ｐ＜０．０１，发铜含量为７．４×１０－６±１．２×１０－６，亦低于对照组（９．８×１０－６±１．３×１０－６）．Ｐ＜０．０５；发锌含量为１６９．２×１０－６±２６×１０－６，与对照组（１７２．５×１０－６±２８×１０－６）基本相同，Ｐ＞０．０５．     

火焰原子吸收光谱法测定铅锌混合精矿中的氧化镁

对火焰原子吸收光谱法测定铅锌混合精矿中氧化镁的仪器工作条件,基体、杂质干扰,释放剂和酸度等进行了试验。在氯化锶和EDTA的盐酸介质中,采用空气-乙炔火焰测定氧化镁,不受铅、锌基体的干扰。方法简便、准确,线性范围为0～3μg/mL,相关系数r=0.9997,加标回收率为98.8％～102.6％,RSD<5.0％,测定范围为0.01％～3％。     

Electrochemical deposition onto self-assembled monolayers: new insights into micro- and nanofabrication

Pattern transfer with high resolution is a frontier topic in the emerging field of nanotechnologies. Electrochemical molding is a possible route for nanopatterning metal, alloys and oxide surfaces with high resolution in a simple and inexpensive way. This method involves electrodeposition onto a conducting master covered by a self-assembled alkanethiolate monolayer (SAMs). This molecular film enables direct surface-relief pattern transfer from the conducting master to the inner face of the electrodeposit, and also allows an easy release of the electrodeposited film due their excellent anti-adherent properties. Replicas of the original conductive master can be also obtained by a simple two-step procedure. SAM quality and stability under electrodeposition conditions combined with the formation of smooth electrodeposits are crucial to obtain high-quality pattern transfer with sub-50 nm resolution.     

Photopolymerization of Butyl Methacrylate in the Presence of Nanoparticles of ZnO,Sensitized to Visible Light with Xanthene Dyes

The photopolymerization of butyl methacrylate in isopropanol with participation of nanoparticles of wide-gap semiconductor ZnO has been studied. The possibility of sensitizing ZnO nanoparticles to visible light with a series of halogenated fluoresceins has been established. The rate of photoinitiation of polymerization in the systems studied is principally determined by the rate of electron transfer from the photoexcited molecule of the sensitizer into the conduction zone of the semiconductor nanoparticles.     

Flow injection method for the fluorimetric determination of Zn with 8-(benzenesulphonamido) quinoline

The development of a fluorimetric method for the determination of zinc, based on the fluorescence of the zinc-8-(benzenesulphonamido) quinoline chelate in a micellar medium of sodium dodecylsulfate, is reported. The detection limit is 0.2 g l^–1, the working range is 0.5–700 g l^–1, and the sample throughput is 145 h^–1. The method was evaluated for the determination of zinc in food samples.A batch procedure for the simultaneous determination of zinc and cadmium, based on the synchronous and derivative spectra, is also proposed.     

Thermodynamics of ion association. Part XXIII. Copper,zinc, and cadmium complexes of some dipeptides

Calorimetric and potentiometric studies have been made at 25°C of the formation of zinc and cadmium complexes of diglycine and of the copper complexes of glycylsarcosine, glycineamide, glycylproline, glycyl-l-alanine, -alanylglycine, and glycyl--aminobutyric acid. In addition, a potentiometric investigation has been made of the formation of copperl-alanyl-l-alanine complexes. The data have been used to calculate G, H, and S values for all the equilibria involved and, in the case of copper, these data strongly support a common structure for all the mono complexes at lower pH in which the copper is bound to the terminal—NH₂ and the oxygen of the peptide group. At higher pH, thermodynamic functions have been determined for the dissociation of the peptide hydrogen atom which is labilized by the copper atom.     

Substrate-controlled highly diastereoselective synthesis of primary and secondary diorganozinc reagents by hydroboration/boron-zinc exchange sequence

The scope of substrate-controlled diastereoselective hydroborations can be considerably enhanced by a boron-zinc exchange reaction, providing organozinc derivatives that react with a broad range of electrophiles. Even normally unreactive boronic esters, obtained by Rh-catalyzed hydroboration with catecholborane, react readily with iPr2Zn providing the corresponding zinc reagents in high diastereoselectivity.     

Sequential extraction-spectrofluorimetric determination of ultratraces of zinc using cryptand 2.2.1 and eosin

A highly sensitive and selective spectrofluorimetric method has been developed for the determination of ultratraces of zinc, based on solvent extraction with 1,2-dichloroethane of the ion-pair formed between eosinate anion and the positively charged cryptate of zinc with cryptand ethers. The detection limit for zinc is 1.5 ng/ml, and the linear working range up to 200 ng/ml. The relative standard deviation is 1.8% at the 100 ng/ml level. The proposed method has been tested for determination of zinc in coal and fly ash.     

Synthesis,Crystal Structure and Thermoanalysis of Complex of Zn(II) with Aminomethanesulfonic Acid-5-bromosalicylaldelyde Schiff Base

1 INTRODUCTION There is considerable interest in the study of Schi- ff-base complexes containing sulfur and complexes of amino acid Schiff-bases[1~8] due to their antiviral, anticancer and antibacterial activities. Furthermore, zinc, as one of the most important trace elements, plays a versatile role in biological systems due to its structural and catalytic roles in enzymes[9, 10]. There- fore, many efforts have been expended on the study of synthetic analogues of zinc enzymes in the hope…