Phenazinee di-N-oxide radical cation and its reactions with hydrocarbons

The absorption spectra of phenazine di-N-oxide radical cation (OPO^+·) in dichloromethane were recorded by the spectroelectrochemical method in the range from 300 to 700 nm. The reactions of the electrochemically generated OPO^+· withpara-substituted toluenes, ethylbenzene, and cumene were studied. Using differential cyclic voltammetry, relative rate constants of reactions of OPO^+· with substrates were determined; their correlations with ⁺ para constants of substituents gives p = -2.7, which attests to the nonradical character of the reaction of OPO^+· with RH. This conclusion is confirmed by the study of the effect of O₂ on oxidation of ethylbenzene and cumene.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1992–1998, August, 1996.     

A comprehensive study of isoskeletal analogs of dibenzo[a,c]anthracene

While reviewing the chemistry of cyclopentadienone derivatives and aza isoskeletal analogs of dibenzo[a,c]anthracene, additional molecular orbital (MO) and spectroscopic results and insights are presented. The MO tendency for coplanarity of phenyl substituents on benzenoids is demonstrated. Perpendicularly oriented phenyl substituents resulting from steric interactions strongly shield appropriately situated protons in NMR spectra. The principles of alternating polarity and parallel correspondence in conjunction with MO methods are used to relatively order aza arene isoskeletal analogs according to their chemical properties. Since less than 1.87% of the isoskeletal analogs of benzo[a,c]-anthracene have been reported, this summary work will help one to forecast the major chemical properties of those not yet synthesized.A preliminary account of this work was presented at the 23rd ACS Midwest Regional Meeting, University of Iowa, Iowa City, Nov. 17, 1988     

Thermodynamic study of anthrone,coumarin and phenazine

Anthrone, coumarin and phenazine were studied by combustion calorimetry of small amounts of substance, sublimation calorimetry, neat capacity measurements and differential thermal analysis.The thermodynamic quantities derived at 298.15 K allowed us to determine some energy values related to molecular structure which enabled us to realize a comparative study for the two isomers: chromone and coumarin, and determine an enthalpy value for some intramolecular chemical bonds in the molecules studied.

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Zusammenfassung Mittels Verbrennungskalorimetrie kleiner Substanzmengen, Sublima-tionskalorimetrie, Wärmekapazitätsmessungen und DTA wurden Anthron, Kumarin und Phenazin untersucht.Die bei 298.15 K erhaltenen thermodynamischen Größen gestatten die Bestimmung einiger Energiewerte bezüglich der Molekülstruktur, die uns in die Lage versetzen, eine vergleichende Studie der zwei Isomere Chromon und Kumarin zu erstellen und die Enthalpiewerte für einige intramolekulare Bindungen in den untersuchten Verbindungen zu bestimmen.

     

Synthesis and Crystal Structure of a New Two-dimensional Manganese Coordination Polymer： [Mn（L）（1,4-bdc）]

A new coordination polymer,[Mn(L)(1,4-bdc)] (L=11-fluoro-dipyrido[3,2-a:2,3-c]phenazine,1,4-bdc=benzene-1,4-dicarboxylate),has been synthesized through the hydrothermal method and characterized by elemental analysis,IR and single-crystal X-ray diffraction.It crystalli-zes in triclinic,space group P1 with a=9.7544(9),b=10.8254(10),c=11.5288(10),α=114.1300(10),β=96.6110(10),γ=105.0390(10)°,V=1038.62(16)3,Z=2,C 26 H 13 FMnN 4 O 4,M r=519.34,D c=1.661 g/cm 3,F(000)=526,μ(MoKa)=0.691 mm-1,R=0.0405 and wR=0.0977.The 1,4-bdc dianions link the neighboring Mn(II) atoms to yield a two-dimensional layer structure.The L ligands are attached on both sides of the layer.The π-π interactions between the L ligands of neighboring layers result in a three-dimensional supramolecular architecture.     

The chemical oxidative polymerization of aniline in water: Raman spectroscopy

The structural changes of aniline oligomers and polyaniline, associated with oxidation of aniline with ammonium peroxydisulfate in aqueous solutions without any added acid, were studied. The reaction was quenched at various times and the films deposited on silicon windows have been studied in detail by Raman spectroscopy, at excitation wavelengths 633 and 514 nm. The presence of substituted phenazine structural units, in addition to ordinary benzenoid, quinonoid, and semiquinonoid structures, has been proved by the appearance of characteristic Raman bands at 1645–1630, 1420–1400, 1380–1365, ∼575, and ∼415 cm⁻¹. The remarkable differences of the Raman spectra of oligoanilines, precipitated in the first phase of oxidative polymerization, and polyaniline nanotubes and nanorods, formed in the second stage of reaction, are discussed. Copyright © 2008 John Wiley & Sons, Ltd.