Spectroscopic characterization of Cu(II) complex of l-phenylalanine and d,l-tryptophan.
Journal - Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
In this work, the reactions involving l-phenylalanine and d,l-tryptophan in the presence of Cu(II) ion were studied. Optimum conditions for the reactions were established as pH 7 and lambda=641nm. When the reaction was kinetic, it was observed that the following rate formula was found as dA/A(n)=kdt and k=3.2x10(-4)s(-1), according to absorbance measurements. Using a perpetual change curve, the ratio of [Cu]/[Cu]+l-phenylalanine+[d,l-tryptophan] was found 1:1:1. According to this result, one molecule of l-phenylalanine and one molecule of d,l-tryptophan react with one molecule Cu(II) ion.Copyright © 2009 Elsevier B.V. All rights reserved.
Kinetic spectrophotometric method for o-phenylenediamine in the presence of gold(III).
Journal - Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy (England )
From the color developing reactions of o-phenylenediamine oxidizing agent and gold(III), the kinetic reactions between both of them in aquaeous solutions were studied using spectrophotometric and differential method. Light absorbances in the visible spectral range are measured as a function of mole fractions of phenylenediamine at a fixed gold(III) concentration and as a function of mole fraction of gold(III) at a fixed o-phenylenediamine concentration at periodic time internal. In the differential method, which was suggested by van't Hoff, one deals with the actual rates of reactions as determined by measuring the slopes of absorbance-time curves. Optimum condition of the reaction were established as pH 6 at lambda=466 nm and room temperature. When the oxidation of o-phenylenediamine by gold(III) was investigated, it was observed that the following rate formula and rate constant were found: v=k[Au+3]1/2[o-phenylenediamine]1/2, k=2.33x10(-2) s-1.
|ISSN : ||1386-1425|
|Mesh Heading : ||Cations Gold Hydrogen-Ion Concentration Kinetics Oxidation-Reduction Phenylenediamines Spectrophotometry chemistry|
|Mesh Heading Relevant : ||chemistry chemistry|