A representative of p,p,p-trihalogenylides: synthesis and structure

The representative of P,P,P-trichloroylides-5-methyl-2-phenyl-4-(trichlorophosphoranylidene)-2,4-dihydro-3H-pyrazol-3-one-was synthesized. Its constitution was confirmed by 1H, 13C, and 31P NMR spectroscopy and by X-ray analysis. Some chemical properties were studied and compared with ones of P,P,P-trimethylylide-5-methyl-2-phenyl-4-(trimethylphosphoranylidene)-2,4-dihydro-3H-pyrazol-3-one. DFT calculations of the model molecules were carried out.     

On-fiber photodegradation after solid-phase microextraction of p,p'-DDT and two of its major photoproducts,p,p'-DDE and p,p'-DDD

The potential of performing photochemical studies in solid phase microextraction (SPME) fibers, "photo-SPME", to study the photodegradation of p,p'-DDT and two of its major degradation products, p,p'-DDE and p,p'-DDD, is shown. Analyses were carried out by gas chromatography mass spectroscopy detection. DDT was extracted from aqueous solutions using five different commercial coatings. The fibers were then exposed to UV light emitted by a low-pressure mercury lamp. After 30 min of irradiation, the degradation of DDT only occurred in polydimethylsiloxane fibers. The on-fiber degradation kinetics of p,p'-DDT was studied from 2 to 60 min. A large number of photoproducts were generated and their kinetic behavior was studied. In order to clarify the possible photoreaction pathways for DDT, individual water solutions containing p,p'-DDD or p.p'-DDE were prepared and photo-SPME was performed for each compound at different irradiation times. On the basis of the photoproducts identified, some photodegradation pathways are proposed. Finally, aqueous photodegradation studies followed by SPME were performed and compared to the photo-SPME. This work will show the enormous potential of photo-SPME to perform photodegradation studies.     

Ion-exchange measurement in biological samples by (p,X) and (p,p) reactions

A method of analysis by ion-exchange in biological samples using (p, X) reactions and back-scattering of charged particles is proposed. Sensitivity and rapidity are the principal qualities of this method.     

Friedel-Crafts Polymers. 8. Friedel-Crafts Polycondensation of β-Resorcylic Acid or Resorcinol with p-Xylylene Dichloride,p,p′-Dichloromethyldiphenyl Ether,and p,p′-Dichloroacetyldiphenyl Ether

Friedel-Crafts polycondensation of β-resorcylic acid (BRA) with p-xylylene dichloride (PXDC) or 4,4′-dichloromethyldiphenyl ether (DDE) in dioxane could be effected without simultaneous decarboxylation of BRA. The similar polycondensation of BRA with PXDC, DDE, or 4,4′-dichloroacetyldiphenyl ether (DADE) in nitrobenzene or in the absence of solvent at 150°C was associated with decarboxylation of BRA. Polymers having structures isomeric with those of the polycondensation product of BRA formed with subsequent in situ decarboxylation were prepared by Friedel-Crafts polycondensation of resorcinol with the above dichlorides. All the polymer samples were characterized, and those with related structures were compared. The ion-exchange properties of the polymer sample prepared from BRA and DDE in dioxane were studied.     

Structure of acetylation products of p,p′-dialkoxydiphenylalkanes

Russian Chemical Bulletin -     

Silicon transitions, 3p 2→→3p n f (n=4, 5) and 3p 2→→3p 6p,detected in the multiphoton dissociation of phenylsilane

Fragmentation to neutral atoms has been observed in the laser photolysis of phenylsilane, C₆H₅SiH₃. A tunable dye laser (UV region) was used both to photolyze the molecule and to probe the resulting fragments. Atomic silicon and carbon lines (two photon resonances) are prominent in the multiphoton dissociation/ionization spectrum of phenylsilane.     

Chromatographic properties of fullerene modified with liquid crystal p, p′-azoxyphenetol

Stationary phases for gas chromatography based on liquid crystal p,p′-azoxyphenetol applied onto Chromaton N-AW bearing a layer of C₆₀ fullerene were studied. The thermodynamic properties of the adsorption of n-alkanes and n-alcohols on the mesogen surface were studied at low occupancies. Test mixtures of structural isomers of substituted benzene and polycyclic aromatic hydrocarbons were analyzed in a wide temperature range from 100 to 240°C.     

Quantitative analysis by (p,X) and (p, γ) reactions at low energies

Production of atomic X-rays and nuclear γ-rays by bombardment with 0–3 MeV protons of thick targets is described. In the case of low-Z atomic X-rays, the absorption in the target is very large, while in the case ofK X-rays from high-Z atoms or for γ-rays, this phenomenon is negligible. Both of these reactions can be used for analysis of elements from F to U, and the sensitivities and the accuracies of the determinations are discussed. A table is given showing the γ-ray energies observed in 11 substances and the limits of sensitivity.     

Cyclization of p,p′-disubstituted diphenylamines to 1-aryl-3-acetyllepidinium salts

The effect of several substituents in the p,p positions of diphenylamine on the cyclization of these amines with formaldehyde and acetylacetone in acid media was investigatedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 659–661, May, 1972     

Fonctions d'excitation des reactions nucleaires:23Na(p,p′γ)23Na,23Na(p,αγ)20Ne et23Na(p,α0)20Ne entre 500 et 1700 keV

Thin targerts obtained by sodium implantation in a layer of silica were used to establish the true excitation functions of the nuclear reactions in question. Many resonances are observed in the energy range explored and their half-widths and the cross-section values at the maxima have been evaluated. The potential performances allowed by these resonant nuclear reactions are examined from the viewpoint of their application to measurements of sodium concentration profiles in the surface region of solids.

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Stagiaire CEA (Boursier 3ème cycle de la DGRST).     

Chlorides, oxochlorides, and oxoacids of 1,8-diphosphanaphthalene: a system with imposed close p...p interaction

Several new 1,8-diphosphanaphthalene oxochloro compounds and oxoacids were prepared and fully characterized. The new compounds are discussed in the broader context with other known congeners to demonstrate the variability of the diphosphanaphthalene scaffolding's bonding patterns. Three principal modes of interaction of the phosphorus moieties were observed in the series: bonding, bridging, and repulsive, resulting respectively in none, moderate, and substantial crowding and distortions. The unexpected dimeric diphosphaacenaphthene anion has been obtained from disproportionative hydrolysis of Nap(PCl(2))(2) (Nap = naphthalene-1,8-diyl).