Synthesis of 4-aroyl-1,2,4-triazolidin-3-ones via ring extension in reactions of 1,2-di-and 1,2,3,3-tetraalkyldiaziridines with aroyl isocyanates

Reactions of 1,2-di-and 1,2,3,3-tetraalkyldiaziridines with aroyl isocyanates involve opening of the diaziridine ring through cleavage of the C—N bond followed by cyclization of the zwitterionic intermediate into 4-aroyl-1,2,4-triazolidin-3-one derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 534–538, March, 2006.     

Sterically controlled cyclization of 3′,4′,5,7-tetramethyldihydroquercetin amidophosphites. New synthesis of phostones

A new sterically controlled reaction of α-hydroxyketones with phosphorus acid triamides resulting in new four-membered phostones is reported.     

Interatomic interactions in the crystal of (C4H11N2)2(C4H12N2)[Mo(CN)8]: comparison of two approaches

Two approaches to the crystal packing analysis, namely the topological analysis of the electron density distribution function in terms of the quantum theory Atoms in Molecules and the stereoatomic model, were compared as applied to the crystal structure of (C₄H₁₁N₂)₂(C₄H₁₂N₂)[Mo(CN)₈]. The data obtained by analyzing the quasi-static electron density distribution function provide an estimate of the scope of applicability and the accuracy of the stereoatomic model for the evaluation of the volume of the complex-forming atom and the determination of a system of intermolecular interactions.     

Features of chemical bonding within the Fe(NO)<Subscript>2</Subscript> fragment for crystalline bis(thiosulfate) tetranitrosyl diiron tetramethylammonium salt as an example according to high-resolution X-ray diffraction data

Results of the study of the experimental charge density function for a crystal of the watersoluble {(СH₃)₄N+}₂[Fe₂(S₂O₃)₂(NO)₄] iron complex are presented. An inequality of two NO ligands at the same metal atom follows from the results of topological analysis of the charge density reconstructed particularly by using the “invariom” model. The inequality also reproduces that in the earlier studied complex Fe(SC₂H₃N₃)(SC₂H₂N₃)(NO)₂]?0.5H₂O, which is not caused by a superposition of spin states. Crystal packing analysis demonstrates the absence of a significant influence of solvation effects on the observed features of chemical bonding in the Fe(NO)₂ fragment.     

Laser induced gratings in CdS

The diffraction from laser-induced gratings is observed in CdS at low temperature in the spectral region of the absorption edge. The excitation intensity is varied from about 100 W/cm² to 1 MW/cm². The reasons for the formation of gratings are a broadening of the excitonic absorption band, a new resonance due to two polariton transitions to the biexciton and the formation of an electron-hole plasma with increasing excitation intensities.     

Optical modes in wavelength-sized organic microcavity structures

We show the impact of lateral structuring on the optical properties of organic thin films in microcavities. The active material tris-(8-hydroxy quinoline) aluminium (Alq₃) was deposited using shadow mask evaporation, resulting in various micron sized shapes. A simplified box model is employed to describe the steady state electric field distribution in these mesa cavities. The complex mode structure measured in transmission and photoluminescence is confirmed by a transfer matrix calculation and a Fourier transform of the internal electric field distribution.     

Luminescence and gain spectroscopy of disordered CdS1−x Se x under high excitation

The absorption-, reflection-, and luminescence spectra of CdS_1–x Se _x are measured under low excitation. The luminescence under high excitation is also observed. For the first time, the gain spectra of disordered crystals are investigated with the excite- and probebeam technique to get a better understanding of the high density electron-hole pair system in this type of materials. We compare the results with those obtained in pure CdS and CdSe.     

Cover Picture

The cover picture shows the single-crystal X-ray structure for C(60)F(18), the first fully characterized aromatic fullerene, possessing a flat and fully delocalized hexagonal benzenoid ring embedded at the center of the fluorinated crown. The bond lengths in this hexagon are all of equal length (1.372 ?). The un-addended part of the molecule possesses the normal C(60) fullerene structure so that the overall appearance is that of a tortoise shell. C(60)F(18) is potentially an important building block for donor-acceptor derivatives with photovoltaic/photonic applications, combining enhanced cage electron withdrawal, with a vacant area for location of donors. The unique geometry also makes the molecule a hexasubstituted benzene, which may be able to participate in eta(6) coordination to metallic species. Details on this tortoise molecule are described by Slovokhotov, Boltalina, and Taylor et al. on p. 3273 ff.