Electric generators of singlet delta oxygen for an oxygen-iodine laser

Experimental and theoretical research into electric generators of singlet delta oxygen (SDO) for an oxygen-iodine laser made at the Lebedev Physics Institute and TRINITI is discussed. Breakdown and current-voltage characteristics of self-sustained electric discharge in SDO were studied both experimentally and theoretically, indicating that SDO and pure oxygen have quite different electric features. The electric properties and spectroscopy of an e-beam sustained discharge (EBSD) in oxygen and oxygen gas mixtures were experimentally studied. A comprehensive numerical model describing SDO kinetics in different kinds of discharge was developed. The pulsed EBSD in pure oxygen and its mixtures with noble gases was shown to be very unstable and characterized by low input energy. When adding small amounts of carbon monoxide or hydrogen, the electric stability of the EBSD increases, the specific input energy (SIE) per molecular component being more than order of magnitude higher and coming to 6.5 kJ/(l atm(O₂ + CO)) for the gas mixture O₂: Ar: CO = 1: 1: 0.1. Theoretical calculations demonstrated that, for an SIE of 6.5 kJ/(l atm), the SDO yield may reach ∼20%, exceeding its threshold value needed for oxygen-iodine laser operation at room temperature. The calibration of the optical scheme for measuring the SDO absolute concentration and yield using the detection of luminescence of the SDO going from a chemical SDO generator was performed. The measurement of the SDO yield demonstrated that it was ∼10.5% for an SIE of ∼3.0 kJ/(l atm(O2 + CO)), which is about 1.5 times less than the results of theoretical calculations for such an SIE. SDO production in RF slab discharge ignited in oxygen gas mixtures was experimentally studied, experimental SDO yield being about 10%. The choice of electrode material was demonstrated to be very important. Original Text ? Astro, Ltd., 2006.     

A methodology for synthesis of primary o-phenylenebisphosphines and o-chlorophenylphosphines

On the basis of the reaction of ethynediylbisphosphonates and chloroethynylphosphonates with classical donor alka-1,3-dienes, a general strategy for synthesis of o-bisphosphanylbenzenes and o-chlorophosphanylbenzenes, which includes two consecutive steps: Diels-Alder condensation → aromatization of the carbocyclic phosphonate (bisphosphonate) formed → reduction of the phosphonate groups, was developed. Convenient procedures are devised for aromatization of phosphorus-containing cyclohexa-1,4-dienes and for reduction of o-phenylenebisphosphonates and o-clorophenylphosphonates to primary phosphines. A series of new alkylsubstituted phosphonic chlorides were prepared, and a possibility of functionalization of methylsubstituted o-phenylenebisphosphonates and o-clorophenylphosphonates by the methyl groups is demonstrated.     

Reaction of Malonic Acid Derivatives with Acetylenic Diphosphonates

The primary addition products in the reactions of malonic esters, cyanoacetic esters, and malononitrile with acetylenediphosphonates in acetonitrile in the presence of anhydrous potassium carbonate are potassium derivatives, viz. esters and nitriles of the corresponding 2-alkoxycarbonyl(or 2-cyano) -3,4-bis(di-alkoxyphosphinoyl)-2-potassiobut-3-enoic acid. Further hydrogen replacement for potassium in the nitriles is accompanied by isomerization involving double-bond shift and geometry change. (E)- and (Z)-3,4-bis(dial-koxyphosphinoyl)-2-cyano-2-potassiobut-3-enenitriles (the alkoxy groups are CH₃O and C₂H₅O) are crystalline compounds; they were isolated and characterized.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 11–20.Original Russian Text Copyright © 2005 by Shekhadeh, Didkovskii, Dogadina, Ionin.     

Syntesis, antifungal and antiviral activity of hydrophosphoryl derivatives of lucensomycin

A reaction of polyene macrolide antibiotic, lucensomycin, with aromatic aldehydes and hypophosphorous acid results in formation of its hydrophosphoryl derivatives. Physicochemical and biomedical properties of the synthesized lucensomycin derivatives were studied. Biological examination showed that hydrophosphoryl lucensomycin derivatives were less toxic medicines than original antibiotic and they are of higher antifungal and antiviral activity.     

Synthesis of bromine-substituted cyclohexenylphosphonates

Bromination of cyclohexa-1,4-dienylphosphonates yields new substituted 4,5-dibromocyclohexene-1-phosphonates. The structure of obtained compounds was confirmed by ¹H, ¹³C and ³¹P NMR spectra.     

Frequency conversion of CO laser radiation in the ZnGeP<Subscript>2</Subscript> nonlinear crystal

The experimental results of the study of CO laser frequency doubling in ZnGeP₂ and GaSe nonlinear crystals of high optical quality are presented. A multifrequency low-pressure Q-switched CO laser and a selective pulsed electroionization mode-locked CO laser with cryogenic cooling were used in the experiments. The highest external factor of radiation conversion into the second harmonic of the pulse-periodic Q-switched CO laser and pulsed mode-locked CO laser was 1% and 3.5%, respectively. Theoretical calculations showed the possibility of obtaining far IR and terahertz radiation using difference frequency generation of CO laser lines in these crystals.