Comparison of figures of merit for fluorimetric analysis of rhodamine complexes of gallium and indium by excitation with pulsed laser and by xenon arc sources

Optimum conditions have been established for formation and extraction of indium-Rhodamine complexes, and limits of detection found for fluorimetric determination of gallium and indium by means of Rhodamine dyes, using the excitation with pulsed laser and xenon arc sources.     

Functional derivatives of thiophenes

2,3-Polymethylene-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine derivatives were obtained by reaction of esters of α-aminothiophene-β-carboxylic acids with lactame or α-aminothiophene-Β-carboxylic acids with lactims. Desulfuration of the thienopyrimidines obtained in this manner is a convenient method for the synthesis of pyrrolo-, pyrido-, and azepino[1,2-a]pyrimidine derivatives.     

CNDO/2 calculations of some polyazaindenes

The theoretically estimated dipole moments of indolizine, imidazo[1,2-a]pyridine, imidazo-[1,5-a]pyridine and of pyrazolo[ 1,5-a]pyridine obtained by the CNDO/2 approximation have been compared with the experimental values. The bond angles and bond distances for these polyazaindenes have been estimated.     

Structures of 2-hydroxypyridine and its vinyl derivatives

The PMR, Raman, and UV absorption spectra of 2-hydroxypyridine and its vinyl derivatives were investigated. Their electrochemical reduction was studied, and a quantum-chemical analysis of them was performed. It was concluded that the structure of 2-hydroxypyridine in proton-donor solvents is mesomeric, and its wave function, to a first approximation, is a linear combination of the wave functions of the 2-pyridone and zwitterion models. The contribution of the wave functions of each of the models depends substantially on the concentration of the solution and the nature of the solvent. An assumption was made regarding the presence of dynamic conjugation between the vinyl group and the ring in vinyl derivatives of 2-hydroxypyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 95–102 January, 1972.     

Researches on benzodiazines

2-R-Quinazolones have been synthesized (R=Me, Ph,-pyridyl,-furyl), and subsequently the 4-chlorides and the corresponding 2-R-4-hydrazinoquinazolines were obtained. By the reaction of orthoformic ester and nitric acid on the hydrazines, 5-R- [3, 4-c]-s-triazoloquinazolines and 5-R- [1, 5-c] tetrazoloquinazolines were prepared, respectively. The compounds in which R=Me differ considerably from compounds with other groups, both in color and stability of intermediate reaction products. 5-R- [1, 5-c] tetrazoloquinazolines are hydrolyzed by HCl into quinazol-4-ones.For Part IV see [1].     

Spectral study of the conversion of porphyrins during interaction with molecular negative ions

In the interaction of ethioporphyrin and of several of its metal derivatives with negative ions of pyridine and anthracene in tetrahydrofuran solutions, an electron transfer takes place which results in the conversion of the pyridine and anthracene ions into neutral molecules, whereas the molecules of the pigment are first transformed into monovalent anions and subsequently into the di-, tri-, tetra-, and sometimes even into the hexavalent anions. In the first stage of this interaction, ferriethioporphyrin is reduced to ferro-ethioporphyrin, whereas the unmetallized pigment and its copper complex are transformed into the disodium derivative of ethioporphyrin. When the temperature is lowered, the rate of the electron transfer from pyridine ions to zinc-ethioporphyrin is decreased, and illumination leads to a substantial rate increase. The photochemical sensitivity of this system is possibly linked to the formation of stable complexes between pigment molecules and pyridine ions.     

Preparation of block copolymers by use of peroxide-terminated prepolymer

Block copolymers containing poly(tetramethylene oxide) and poly(methyl methacrylate) segments were prepared. A commercially available poly(tetramethylene oxide) terminated with tolylene diisocyanate was capped with tert-butyl hydroxymethyl peroxide and the resulting prepolymer peroxide was used as a free-radical initiator of vinyl polymerization. Block copolymers formed in temperature-programmed vinyl polymerizations possessed improved impact strengths over poly(methyl methacrylate) from 0.35 to 1.18 for a fixed (nonoptimized) block length of poly(tetramethylene oxide).     

Metal coordination polymers. II. Molecular weight studies of beryllium phosphinate polymers in toluene

The number-average molecular weights of beryllium 4-biphenyl(phenyl)phosphinate, di-n-pentylphosphinate, di-n-heptylphosphinate, and trifluoromethyl(phenyl)phosphinate are degraded by the presence of water in toluene. It is proposed that easily hydrolyzable P? O? P bonds contribute, in part, to the bonding of these polymers.     

Reactions of Vanillin and Vanillal Esters with 6-Quinolylamine and Phenidone

Previously unknown 2-methoxy(or ethoxy)-4-(11-oxo-9-phenyl-7,8,9,10,11,12-hexahydrobenzo[b][4,7]phenanthrolin-12-yl)phenyl esters of carboxylic acids were prepared by ternary condensation of vanillin or vanillal alkanoates with 6-quinolylamine and Phenidone. According to the ¹H NMR spectra, the target products are formed as mixtures of diastereomers.     

New Method of Analysis of Intermolecular Contacts in the Crystal Structure: π-Complexes

A new method for analysis of intermolecular contacts in the crystal structure based on characteristics of the Voronoi-Dirichlet polyhedra (VDP) is considered using metal π-complexes as examples. The crystal data of the compounds were used to determine the surface area of the VDP faces corresponding to all intermolecular contacts in one π-complex, the total volume of the pyramids with VDP faces as bases and the nuclei of atoms involved in the intermolecular contacts at the vertices, and the total solid angle at which the “intermolecular” VDP faces are seen from the corresponding nuclei of the molecule. A common linear correlation between the enthalpy of sublimation of π-complexes and saturated or unsaturated hydrocarbons and the molecular VDP characteristics was elucidated. On the basis of the results, the enthalpies of sublimation were calculated for some iron π-complexes (for which data on the crystal structure were available) and C₆₀ and C₇₀ fullerenes.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 7, 2005, pp. 495–505.Original Russian Text Copyright © 2005 by Serezhkin, Shevchenko, Serezhkina.