Etude par RPE de l'Ion NO2−2 dans une apatite nitrée

A calcium phosphate apatite which contains some different nitrogen oxides is studied by the ESR technique. NO^2?₂ ions are evidenced and characterized. They stay in the apatite channels with their OO direction along the channel axis. ESR experiments at different temperatures show that these ions rotate around this axis when the temperature becomes higher than that of liquid nitrogen.     

Fermi and Coulomb correlations in the 21 S state of the helium isoelectronic sequence

The Fermi and Coulomb holes of the 2¹ S state of the helium isoelectronic sequence are investigated. Several interesting differences between the results obtained and those which might be expected on the basis of the corresponding 2³ S state are pointed out and discussed.     

Catalytic desulfurization of condensed thiophenes by means of methanol

Desulfurization of dibenzothiophene, two methyldibenzothiophenes, and phenanthro[4,5-bcd]-thiophene to give 60-80% yields of hydrocarbon products was effected by means of a sulfided molydena catalyst plus methanol at 450° and a pressure of ca. one atmosphere. The methanol functions both as an in situ hydrogen donor and as a methylating agent.     

EPR-untersuchungen an carbonsäureestern—II : Radikalanionen der thion- und dithiobenzoesäureester

Alkyl thione (2) and dithiobenzoates (3) as well as their aryl substituted derivatives 4 and 5 may be converted into radical anions by in situ electroreduction.—The EPR spectra of 2–5 are measured. Conclusions about the spin density distribution within the aromatic ring and the functional group are drawn from the hyperfine structure coupling constants, g-values and polarographic half wave potentials, whereby the effect of ortho substituents (twisting of the two halves of the molecule) is especially considered.—The results agree sufficiently with MO calculations of the McLachlan type.Inspection of the alkyl coupling constants

shows that the alkyl groups exhibit conformations of minimum steric hindrance of the thiocarbonyl group.     

Rearrangements in cobaltic fluoride fluorinations of cycloalkanes with seven or more ring carbons

Cyclo-heptane, -octane, -decane, -dodecane and -octadecane have been fluorinated in the vapour phase with cobaltic fluoride. The perfluorocarbons obtained revealed varying degrees of skeletal rearrangements. Thus, cycloheptane gave perfluoro-cycloheptane and -methylcyclohexane; cyclooctane gave at least eight fluorocarbons including-bicyclo(3,3,0)octane and -cyclooctane; cyclodecane gave a complex mixture from which were isolated perfluoro cis- and trans-bicyclo(4,4,0)decanes but no perfluorocyclodecane; cyclododecane and cyclooctadecane gave complex fluorocarbon mixtures in which none of the fluorocarbons with the original cycloalkene skeleton could be detected.Tetradecafluorobicyclo(3,3,0)octane gave dodecafluorobicyclo (3,3,0)oct-1(5)-ene and decafluorobicyclo(3,3,0)octa-di-1(5), 2-ene when pyrolysed over iron gauze.The fluorination of cyclooctane also afforded 1$\text{H}$-pentadecafluorocyclooctane which was dehydrofluorinated to tetradecafluorocyclooctene. This was converted to a range of derivatives including dodecafluorosuberic acid, 1,2-dichlorotetradecafluorocyclooctane, 1-methoxy tridecafluorocyclooctene and tetradecafluorocyclooctanone.     

Buchbesprechungen

Ohne Zusammenfassung     

Contribution a l'électrochimie des thiols et disulfures : Partie I. Cystéine et cystine

A study of the electrochemical characteristics of cysteine and cystine was carried out by d.c., a.c. and differential pulse polarography. Up to three waves were observed depending on the concentration and pH. The waves of the two amino acids could be separated in a borate buffer of pH 9.2. Differential pulse polarography made it possible to determine as little 0.12 mg of cysteine and 0.24 mg of cystine per litre.