Complexing reagent

CijHgNj. Made by heating o-pheny-lenediamine with glycerol, nitrobenzene and cone, sulphuric acid. It exists as a monohydrate, m.p. 94" C, or anhydrous, m.p. 117°C. It is used as a complexing reagent in the estimation of Fe and in the preparation of numer-... 

Fluorescence quenching methods wits ai omatic complexing reagents are often recommended for copper (II) determination in water. 

Yet another difference is that laboratory reactions are often done using relatively small, simple reagents such as Br2, HC1, NaBH4, OO3, and so forth, while biological reactions usually involve relatively complex "reagents" called coenzymes. In the hexokinase-catalyzed phosphorylation of glucose just shown,... 

This colour change can be observed with the ions of Mg, Mn, Zn, Cd, Hg, Pb, Cu, Al, Fe, Ti, Co, Ni, and the Pt metals. To maintain the pH constant (ca 10) a buffer mixture is added, and most of the above metals must be kept in solution with the aid of a weak complexing reagent such as ammonia or tartrate. The cations of Cu, Co, Ni, Al, Fe(III), Ti(IV), and certain of the Pt metals form such stable indicator complexes that the dyestuff can no longer be liberated by adding EDTA direct titration of these ions using solochrome black as indicator is therefore impracticable, and the metallic ions are said to block the indicator. However, with Cu, Co, Ni, and Al a back-titration can be carried out, for the rate of reaction of their EDTA complexes with the indicator is extremely slow and it is possible to titrate the excess of EDTA with standard zinc or magnesium ion solution. 

Two other types of host for arenediazonium salts were found by Shinkai et al., the calix[ ]arenes, 11.10 (1987 a, 1987 b) and 11.11 (1988). The hexasulfonated calix[6]arenes 11.10 suppress dediazoniation of substituted benzenediazonium ions in aqueous solution much more efficiently than 18-crown-6. The complexation of calix[ ]arenes 11.11 (n = 4, 6, and 8) with 4 -dimethylaminoazobenzene-4-diazonium ions (11.12) was measured, and was found to be weaker than that of 18-crown-6. It may be that the large difference in behavior between these two types of complexation reagents 11.10 and 11.11 is due to the significantly different diazonium ions used as guests for the two types. Electronically the azobenzenediazonium ion (11.12) is... 

In addition to the influence of the complexation equilibrium constant K, the observed reaction rate of arenediazonium salts in the presence of guest complexing reagents is influenced by the intrinsic reaction rate of the complexed arenediazonium ion. This system of reactions can be rationalized as in Scheme 11-1. Here we are specifically interested in the numerical value of the intrinsic rate constant k3 of the complexed diazonium ion relative to the rate constant k2 of the free diazonium ion. 

Vol. 18. Organic Complexing Reagents Structure, Behavior, and Application to Inorganic Analysis. By D. D. Perrin... 

Perrin, D. D. (1964). Organic Complexing Reagents, p. 269. New York Interscience Publishers. 

A. A. Perejma and L. V. Pertseva. Complex reagent for treating plugging solutions—comprises hydrolysed polyacrylonitrile, ferrochro-moUgnosulphonate Cr-containing additive, waste from lanolin production treated with triethanolamine and water. Patent RU 2013524-C, 1994. 

Scheme 97. Synthesis of optically active 8-methylcanadine (477) via the chromium complex. Reagents a, Cr(CO)6 b, n-BuLi, Me3SiCl c, n-BuLi, Mel d, n-Bu4NF e, Oz. 

Because of the complex nature of gold-containing Cu-Pb-Zn ores, the reagent schemes used are also complex. Reagent modifiers such as ZnS04, NaCN and lime have to be used, all of which have a negative effect on gold flotation. 

The RPIA technology has been enhanced in the Stratus CS system by utilization of a dendrimer-antibody complex in which the analyte-specific capture antibody is covalenty coupled onto a dendrimer. The test packs in the Stratus CS system include dendrimer-capture antibody complex reagent, the alkaline phosphatase labeled antibody conjugate reagent, the substrate-wash reagent and a piece of glass fiber filter paper as the solid phase. Preparation and unique properties associated with these dendrimer-coupled antibody complexes are described below. 

The use of complexing reagents containing two functional groups is an effective method employed for metal ion determination by fluorescence measurement. For example, 8-hydroxyquinoline (3) (Figure 4.8) forms complexes with a large number of metal ions. 

A direct method has been developed for the spectrophotometeric determination of Pd(II) with sodium-1-methyl-l-propylthioxanthate as a complexing reagent in the micellar media. Beer s law was obeyed in the concentration range 0.84-7.5pg/mL for Pd(II) under the optimized conditions. Calibration curve was constructed at the absorption maxima (/.m(ix) i.e. 370nm for Pd(II). Sandell s sensitivity and molar absorptivity have been found to be 0.0060pg/cm2 and 8.6xl04 L/mol/cm for Pd(II). The developed method has been found to be quite simple, rapid, sensitive and reproducible results were obtained. 

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