Synthesis of halogen substituted imidazo[4,5-e][1,4]diazepine-5,8-diones. Cyclic homologs of methylxanthines

Possible routes for synthesis of 2-haloimidazo[4,5-e][1,4]diazepines are discussed. Conditions for chlorination differ for homologs of caffeine, theophylline, and theobromine. For the caffeine homolog, both the 2-chloroand 2,6,6-trichloro products are obtained depending on the synthetic conditionsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 955–958, July, 1992.     

Temperature dependent energy transfer in Ar-O3 collisions

The energy transfer between argon atoms and ozone complexes O3*, excited in the region of the dissociation threshold, is calculated for fixed temperatures (100 K< or =T < or =2500 K) using classical trajectories. The internal energy of ozone is resolved in terms of vibrational and rotational energies. For all temperatures, energy flows from O3* to Ar. The vibrational energy transfer, relative to k(B)T, is very small below 500 K, but gradually increases towards high temperatures. The relative rotational energy transfer, on the other hand, monotonously decreases with T; around 1100 K it falls below the relative vibrational energy transfer. Thermally averaged cross sections for vibrational and rotational energy transfers are also calculated. The implications for the stabilization of ozone complexes in the energy transfer model are discussed.     

New diphthalocyanine complexes of rare-earth metals based on 4,5-isopropylidenedioxyphthalonitrile

A series of the earlier unknown diphthalocyanine complexes of rare-earth metals based on 4,5-isopropylidenedioxyphthalonitrile were prepared. Their compositions and yields depend on the radius of the complexing ion. The synthesized compounds were studied by spectroscopy and electrochemical methods. The redox potentials of the complexes studied change nonlinearly with a decrease in the lanthanide ion radius. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 274—279, February, 2006.     

Effects of H/D-isotope substitution and temperature on the volume characteristics of tetra-n-butylammonium bromide dissolved in methanol and its D-isotopomers

Densities of Buⁿ ₄NBr solutions in MeOH, MeOD, and CD₃OH were measured at salt concentrations of up to 1.5 solvomolality units (nearly 2.63·10^–2 mole fraction) at 278.15, 288.15, 298.15, 308.15, and 318.15 K. The limiting partial molar volumes of Buⁿ ₄NBr dissolved in these alcohols were calculated. The isotope effects in the volume characteristics of the stoichiometric mixture of ions, [Buⁿ ₄N⁺ + Br^–], are mainly due to the vibrational changes in the solvent structure upon deuteration of different molecular fragments. Structural transformations in infinitely dilute solution of Buⁿ ₄NBr in methanol are governed by non-specific solvation of the symmetrical Buⁿ ₄N⁺ cation.     

On the relation between the Jackson and Jung constants of the spacesL p

For any infinitely metrizable compact Abelian groupG; 1pq<,n , the following relations are proved: whereK _pq(G, n, G) is the largest Jackson constant in the approximation of the system of characters by polynomials of ordern, d _pq(G, n, G) is the best Jackson constant,J(L _p(G), L_q(G)) is the Jung constant of the pair of real spaces (L _p(G), L_q(G)), and.Translated fromMatematicheskie Zametki, Vol. 58, No. 6, pp. 828–836, December, 1995.This work was supported by the Russian Foundation for Basic Research under grant No. 95-01-00657.     

Nonreciprocal effects in light reflection by a moving medium

Nonreciprocal effects in light reflection by a medium moving along an interface are considered in a weakly relativistic approximation. It is found that nonreciprocal effects are anomalously large in the vicinity of the Brewster and the total-internal-reflection (TIR) angles when light is reflected by transparent moving media. These effects exceed considerably (by several orders of magnitude) the ratio of the velocity of the reflecting medium to the velocity of light and can be proportional to rather than to under certain conditions. We show new possibilities for the creation a method for investigation of the structure of nonuniform flows with a very small spatial scale (less than one millimeter). This method is based on measurement of amplitude and phase nonreciprocities in light reflection by these flows.Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 11, pp. 1146–1157, November, 1995.