Über Reaktionen von Nitrosophenolen, 4. Mitt.: Reaktion von Nitrosonaphtholen mit Naphtholen

Zusammenfassung Die Reaktion von 1-Nitroso-2-naphthol mit 1-und 2-Naphthol sowie die Reaktion von 2-Nitroso-1-naphthol mit 2-Naphthol in Äthanol und in Äther bei Anwesenheit von HNO₃ gibt 5H-Dibenzo[a,j]phenoxazon-(5) (I), 5H-Dibenzo[a,j]phenoxazon-(5)-14-oxid (II), 5H-Dibenzo[a,h]phenoxazon-(5) (III) sowie 5H-Dibenzo[a,h]phenoxazon-(5)-14-oxid (IV). Es wurde ein Reaktionsmechanismus vorgeschlagen und die Konstitution der hergestellten Verbindungen spektrophotometrisch und potentiometrisch bestimmt.

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The reaction of 1-nitroso-2-naphthol with 2-and 2-naphthol and the reaction of 2-nitroso-1-naphthol with 2-naphthol in ethanol or ether in the presence of nitric acid have been studied. The main reaction products isolated were the dibenzophenoxazones I–IV. The reaction mechanism for their formation is proposed.

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Phthalocyanines and related compounds: XXXVIII. Synthesis of symmetric taurine- and choline-substituted phthalocyanines

Procedures have been developed for the synthesis of a series of metal complexes derived from water-soluble anionic and cationic octa-4,5-carboxyphthalocyanine-taurine and choline conjugates.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1907–1911.Original Russian Text Copyright © 2004 by Mikhalenko, Soloveva, Lukyanets.For communication XXXVII, see [1].This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and Crystal Structure of the [Re2(CH3COO)2Cl4((CH3)2NCOCH3)2] Complex

Compound [Re₂(CH₃COO)₂Cl₄((CH₃)₂NCOCH₃)₂] is synthesized. The influence of parameters of the hydrothermal synthesis under elevated pressure on the yield of a target product and its molecular structure and physicochemical properties is studied. In the neutral complex with cis-arrangement of the bridging acetate and terminal chloride ligands with respect to the multiply bonded Re₂ ⁶⁺ complex-forming center, the Re–Re bond length is 2.2418(3) Å. Dimethylacetamide molecules are in the axial positions, the Re–O bond lengths being 2.304(3) and 2.321(4) Å. The influence of the donor ability of the axial substituents in analogous structures of the rhenium(III) binuclear clusters on the Re–Re and Re–L_ax bond lengths is analyzed.     

High-performance liquid chromatography of in vitro synthesized poly(ADP-ribose) on ion-exchange columns, separation of oligomers of varying chain length and estimation of apparent branching

Separated macromolecular fractions of in vitro synthesized poly(ADP-ribose) by liver nuclei were subjected to ion-exchange chromatography in a programmed high-performance liquid chromatographic elution system. The effects of ionic strength, pH and temperature on the separation of poly(ADP-ribose) chains were determined. Short chain oligomers (up to n = 11) were fractionated into individual components by baseline separation. Each fraction was analyzed for chain length. Trace amounts of Ado(P)Rib(P)Rib(P) found in phosphodiesterase digests were taken as indication of apparent branching. In phosphodiesterase digests of the shorter oligomers, besides traces of the above component, two other digestion products were also observed, presumably representing oligomer termini, one terminal fragment being dominant in short oligomers. Medium and long chain oligomers were partly resolved to individual components, and especially the long oligomers exhibited marked temperature dependent elution patterns. Apparent branching increased with increasing chain length up to about 3% for n = 44 and components presumably indicating termini diminished to mere traces. The adenine spectra of all fractions identified individual components.     

The graphite furnace and its role in atomic spectroscopy

The diversity of applications of the graphite furnace is extraordinary, encompassing the fields of physics, thermochemistry, spectroscopy and analytical chemistry. In this respect, the graphite furnace has been used on a continuous basis as a research tool for nearly a century. Following its introduction as an atomization source for atomic absorption spectrometry by Lvov in 1959, its role in atomic spectrometry expanded considerably to encompass analytical applications in emision, fluorescence, absorption and mass spectrometry. In addition to its conspicuous use as an atomization source in these areas, it is frequently employed as a vaporizer when used in the format of combined and tandem sources with other instrumentation. The unique physico-chemical micro-environment which can be attained within the graphite furnace has also been used to advantage in a number of investigations, including the determination of gas- and solid-phase diffusion coefficients of high-temperature metal vapours, the heats of sublimation of refractory metals, fundamental optical constants and the measurement of the heats of desorption of adatoms from high-temperature surfaces. The range of such applications remains to be more fully explored. The attractive features of this source, viz., the high atomization/vaporization efficiency, comparatively long atomic vapour residence times, controllable chemical and thermal environment and its ability to handle high dissolved solids content samples (100%) serve to ensure its place in analytical atomic spectroscopy for years to come.     

The effect of mechanical activation on the thermal decomposition of chalcopyrite

Experimental results on the influence of preliminary mechanical activation on the thermal decomposition of chalcopyrite are presented and discussed. The following experimental facts were found:

2,6-di-tert-butyl-4-perimidylphenols and their oxidation

1,8-Naphthylenediamine was reacted with 2,6-di-tert-butyl-4-formyl-phenol to produce 2,6-di-tert-butyl-4-(1,3-dihydro-perimidyl) phenol (I). The latter was coverted into 2,6-di-tert-butyl-4-(1H-perimidyl)phenol (II) by oxidizing I with sodium pyrosulfate. When phenol II was oxidized by lead dioxide in toluene and THF, the EPR spectra revealed a 12-component multiplet with perimidyl splitting constants a¹ _N=a³ _N=a_H ^NH=0.2 mT; a_H ^6.7=0.6 mT.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 1, pp. 64–67, January, 1992.     

Study of the absorption spectra and ionic equilibria of cationic-anionic polymethine dyes

The absorption spectra of a number of cationic-anionic polymethine dyes in polar, low-polarity, and nonpolar solvents were studied. It was established that in polar solvents the absorption spectra represent the sum of the absorption spectra of the cation and anion, whereas in nonpolar and low-polarity solvents, in many cases the appearance of a short-wave absorption band is observed, due to interaction of the chromophores of the cation and anion in ion pairs. In solvents of intermediate polarity (for example, in chloroform and ethyl acetate), a concentration dependence of the absorption spectra is observed, determined by the equilibria of ionic dissociation. The ionic dissociation constants of a number of cationic-anionic dyes in chloroform and ethyl acetate were determined by a conductometric method. The thermodynamic data obtained are compared with the spectral data.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2524–2532, November, 1992.     

A comparison of geometric methods with other methods for the characterization of density matrices

Some recently developed geometric methods for characterizing the subset of density matrices within the space of Hermitian matrices are compared with methods commonly used for the approximate characterization of reduced density matrices. The decomposition of a density matrix into components in terms of the reducing basis set is compared with decomposition in terms of representations of U(r).