Pyridinium N-phenolate betaine dyes.

Transition metal complexes with binucleating ligands

T he term solvatochromism is used to descr ibe the pronounced change in position and sometimes intensity of a UVvisible absorption band following a change in the polarity of the medium. When absorption spectra are measured in solvents of different polarity it is found that not only the position but also the intensity and shape of the absorption band can vary, depending on the nature of the solvent. The in uence of solvents on the course of chemical reactions has been studied for a long time, and efforts have been made to correlate equilibrium constants, reaction rate constants, or positions of ultraviolet absorption bands with the so-called ‘‘polarity’’ of the solvent.1 Attempts made to express the polarity in terms of dielectric constant, dipole moment, or other properties of the solvent have not been very successful, largely due to the simpli cations used. 2 The polarity of a solvent is determined by its sol-

https://journals.sagepub.com/doi/pdf/10.1366/0003702011953702

Principles and Applications of Solvatochromism

Surfactants have been used in the development of new methods for colorimetric analysis. Amphiphilic molecules (surfactants, detergents) on dissolution in water from organized molecular assamblies called micelles when an appropriate concentration, the critical micelle concentraiton (cmc), is exceeded. The micelles enhance the solubility of organic compounds in water by rpoviding local nonpolar environments. A simple method for the determination of several metal ions has been developed using diphenyltiocarbazone (dithizone) and a nonionic surfactant, polyoxyethylene tert-octylphenol (Tritonx X-100)

Micellar Colorimetric Determination of Dithizone Metal Chelates

Bicyclic Conformationally Restricted Diamines

Spectrophotometric determination of water in organic solvents with solvatochromic dyes

Analytical application of organic reagents in hydrophobic gel media—I: General principle and the use of dithizone gel☆

The copper(II) and oxovanadium(IV) complexes of a new Schiff base derived from heptane-2,4,6-trione and ethylenediamine were prepared. Of a macrocyclic two-to-two and an open jaw-shaped two-to-one (trione to diamine) condensation product, only the latter gave mononuclear copper (II) and oxovanadium(IV) complexes. The coordinating sites to the metal ion in each complex are discussed referring to the spectroscopic results.

Schiff Bases Derived from Heptane-2,4,6-trione and Ethylenediamine, and Its Copper(II) and Oxovanadium(IV) Chelates

The use of hydrophobic gel particles containing an organic solvent solution of chelating agents is described. With the use of a column of such gel particles, it is possible to trap or concentrate metal ions selectively on the gel particles from very dilute aqueous solution. A method for the semi-quantitative determination of trace amount of metal ions is proposed.

Tairoku Yano

Papers

Spectrophotometric determination of water in organic solvents with solvatochromic dyes

Analytical application of organic reagents in hydrophobic gel media—I: General principle and the use of dithizone gel☆

Schiff Bases Derived from Heptane-2,4,6-trione and Ethylenediamine, and Its Copper(II) and Oxovanadium(IV) Chelates

The Analytical Applications of Organic Reagents in Hydrophobic Gel Media

Analytical application of organic reagents in hydrophobic gel media-IV Selective preconcentration of Cobalt(II) with 1-nitroso-2-naphthol gel.