An IR spectroscopic study of acid centers on the surface of Al,Zr silica gels

Acid centers of Al, Zr silica gels with approximately equal aluminum ion contents (∼2.4% Al₂O₃) and various concentrations of Zr ions were studied by IR spectroscopy using the deuteroacetonitrile molecule as a probe. The surface of such samples was found to contain Lewis acid centers of two types, coordination unsaturated (I) silicon and (II) zirconium ions. An increase in the content of zirconium ions was accompanied by a decrease in the intensity of the 2328 cm⁻¹ band in the IR spectra. This band was characteristic of interaction of CD₃CN with Lewis acid centers of type I. The suggestion was made that this was caused by a decrease in the accessibility of coordination unsaturated silicon ions to CD₃CN molecules.     

Conformational switching in bis(zinc porphyrin) Langmuir-Schaefer film as an effective tool for selectively sensing aromatic amines

A conformational switching of bis(zinc octaethylporphyrin) was observed, for the first time, in a Langmuir-Schaefer film as a consequence of appropriate host-guest interactions. The spectral changes are completely reversible and the high sensitivity (～20ppb) and specificity for aromatic amines open up interesting prospects of this functional material as a performing sensor for amines.     

Porphyrazines as multicenter bases

A critical analysis is made of the existing work on the acid-base properties of porphyrazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1625–1630, December, 1988.     

Infrared study of nitrogen adsorption on alumina

Good agreement of the results of numerical calculations with experimental data shows that the simple representation of a Lewis acid site of an alumina surface as a positive point charge plus van der Waals interaction can describe some characteristics of its interaction with a nitrogen molecule.     

Synthesis and study of the spectral properties of diquinone derivatives of hematoporphyrin IX

Diquinone derivatives of hematoporphyrin IX with different structures of the quinone fragments were synthesized by the method of mixed anhydrides. The compounds obtained were investigated by UV, IR, PMR, and fluorescence spectroscopy. Pronounced quenching of the fluorescence of porphyrin in the porphyrin quinones, which depends on the acceptor properties of the quinones and the spatial orientation of the donor and acceptor, was observed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1324–1330, October, 1991,     

Anreicherung von Spuren Seltener Erden aus Mineralwässern durch Ionenaustausch

In the described analysis of mineral waters, after the throughflow of the sample through a column with Dowex 50 WX 12 in H⁺ form, the main cations are first eluted by 1.6 N HCl and then the rare earths by 6 N HCl. The latter are separated by ion-exchange chromatography on Dowex 50WX8 in NH₄ ⁺ form, the elution being performed with ammonium citrate pH 4.19. The presence of rare earths in the eluate was ascertained spectrophotometrically by means of their reaction with xylenol orange in the presence of cetylpyridinium bromide. In mineral waters from the West-Bohemian spa region it was possible to find traces of trivalent La, Ce, Pr, Nd, Sm + Gd, Y, Dy, Ho, Er, Tm, Yb and Lu.     

A Study of the Competitive Equilibrium in Ion Exchange of Calcium(II) on Zirconium Phosphate in Multicomponent Salt Solutions

A sorption technology for stabilization of multicomponent salt solutions (wines) subject to calcium clouding is being developed on the basis of an inorganic cation-exchanger of Termoksid-3A brand. In this connection the ion-exchange equilibrium on a zirconium(IV) phosphate of Termoksid-3A brand in multicomponent solutions at pH 2.5 – 3.0 was studied. The selectivity series of the sorbent were determined in relation to the solution composition.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 235–239.Original Russian Text Copyright © 2005 by Borovkov, Sharygin.     

Synthesis of Metallofullerenes by Electric-Arc Method with a Surface-Modified Electrode

A method for synthesis of metallofullerenes by electric-arc sputtering of graphite, in which lanthanum compounds are deposited on the surface of a graphite electrode, was suggested. The influence exerted by the amount of deposited lanthanum on the yield of lanthanum was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 566–571.Original Russian Text Copyright © 2005 by Kuz’min, Borovkov, Kolker, Brazhyunas.