Effect of aryl substituents on the rate of dark decolorization of photochromic spirochromenes of the indoline series

The introduction of aryl substituents in the 3 and 7 positions of the indoline spirochromene molecule gives rise to a certain amount of slowing down of dark decolorization in toluene and dioxane; similar changes in the 5, 6, and 8 positions do not change the rate appreciably.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–81, January, 1977.     

Study of the Anglular Structure of Emission from the Radio Galaxy 3C295 in the Decameter Wavelength Range

We present the results of observations of the angular structure of the radio source 3C295 at decameter waves using the URAN-1 and URAN-2 interferometers. It is shown that the radio image of 3C295 at these frequencies differs drastically from the structure of this object observed at higher frequencies. The simplest model of the structure of this radio galaxy, comprising one component with a Gaussian brightness distribution of angular size (7.4 ± 0.4)× (8.7± 0.4) at 25 MHz and (9.1± 0.5)× (10.6 ± 0.5) at 20 MHz, is determined. A decrease in the spectral density of the emission with decreasing frequency, observed below 50 MHz, is explained.     

Effect of magnetic (phase) inhomogeneities on the conductivity of an antiferromagnetic La2CuO4 + δ single crystal at low temperatures

It has been established that, at a strongly nonuniform distribution of oxygen in a La₂CuO_{4 + δ} single crystal, isolated superconducting inclusions can be formed at an average hole concentration not higher than 0.0024 per copper atom. The behavior of the conductivity in a magnetic field below 20 K is consistent with possible existence of a insulating low-temperature magnetic phase (spin density waves), which is typical of cuprates with excess oxygen.     

Über Mannheimsche Flächen

Ohne Zusammenfassung     

Synthesis and spectral characteristics of photochromic 6- and 8-phenyl- substituted indoline spirochromenes

Two photochromic indoline spirochromenes were synthesized. The introduction of a phenyl group into the 6 or 8 position causes a bathochromic shift of the bands in the electronic absorption spectrum of the merocyanine form.     

Synthesis and spectral characteristics of photochromic 1′,3′,3′-trimethyl-6-nitro-7-phenyl-2H-chromene-2-spiro-2′-indoline

5-Nitro-4-phenylsalicylaldehyde, from which the corresponding photochromic indolinespirochromene was obtained, was synthesized. The introduction of a phenyl substituent in the 7 position brings about a substantially smaller change in the longwave band in the electronic absorption spectrum of the merocyanine form than introduction of this substituent in the 8 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 200–203, February, 1976.