Johanna Fruwert

Das Schwingungsverhalten von Diphenylsulfid, Diphenylsulfoxid und Diphenylsulfon

Abstract The vibrational spectra of diphenyl sulphide, diphenyl sulphoxide and diphenyl sulphone have been investigated. On the basis of different orientations of the phenyl groups it was tried to assign the normal vibrations using the spectra of monosubstituted benzene derivatives. It is shown that the orientation causes different conjugations between the phenyl groups and the residual molecule and influences markedly the vibrational behaviour of the three compounds. The model of nonequivalent phenyl groups allows a complete assignment and explains the splitting of the substituent-sensitive vibrations.

Über die substituentenabhängigkeit der Donatorund Akzeptoreigenschaften der Hydroxylgruppe in parasubstituierten Phenolen und Phenol—Anisol-Komplexen

The association behaviour of seven para-substituted phenols in carbon tetrachloride has been studied by i.r. spectroscopy. From the linear relationships between the dimerization parameters and the substituent constants it follows that the association tendency decreases with the increase in the acidity of the phenol. Furthermore the association constants and complex enthalpies of a series of hydrogen-bonded complexes between substituted phenols and anisoles has been measured. The frequency shift ΔνOH in the donor-acceptor complexes indicates that the proton donor strength of the OH-bond increases as the ability of the substituent to attract electrons increases. However, the acceptor strength of the oxygen lone-pairs decreases markedly in the same way. Thus, the strength of the OH⋯O hydrogen bond in phenols is determinated essential by the acceptor function of the oxygen atom.

Infrared spectroscopic investigation of hydroxy-group siting in H faujasites

The total hydroxy-group and the separate high-frequency (h.f.) and low-frequency (l.f.) hydroxy-group concentrations in H faujasites, observed by i.r. spectroscopy and corroborated by other methods, show a dependence of the maximum occupation of h.f. OH groups on the Si/Al ratio of between 15 and 32 OH groups per unit cell for zeolites HY and HX, respectively. In the case of HX zeolites above 70% exchange, decomposition is unavoiable. As a result of band separation the separate amounts of seven kinds of h.f. OH subspecies have been obtained from measurements of their i.r. absorbance and the integrated extinction coefficients of the h.f. OH stretching band for HX and HY zeolites. These subgroups show the same i.r. sub-bands in both HX and HY zeolites, but of different intensities. This may be explained on the basis of different Si/Al ordering schemes by O1H groups bonded to silicon atoms, surrounded by 0–4 Al atoms, and bonded to Al atoms, which are influenced by electrostatic interactions with neighbouring aluminium atoms.

Schwingungsverhalten des syn- und anti-acetaldoxims: 1. Mitt. Schwingungsspektren

Abstract The infrared spectra of CH3CHNOH, CH3CHNOD, CH3CDNOD and CD3CDNOD have been recorded and studied. On the basis of the symmetry properties the normal vibrations were assigned by comparison.

Schwingungsverhalten des syn- und anti-acetaldoxims: 2. Mitt. normalkoordinatenbehandlung

Abstract Normal coordinate calculations on CH 3 CHNOH, CH 3 CHNOD, CH 3 CDNOD and CD 3 CDNOD have been carried out applying the general harmonic valence force field. The calculated frequencies of the normal vibrations considered agree satisfactorily with the corresponding values obtained from the spectra. The potential energy distributions have also been calculated; they were used to interpret the behaviour of characteristic vibrations.

Schwingungsanalyse konformerer 1-Brombutane

Zusammenfassung Die Infrarot- und Ramanspektren von n-Butylbromid wurden im flussigen Zustand aufgenommen. Mit Hilfe einer Normalkoordinatenanalyse gelang es, die auftretenden Banden den Konformationen TT, TG, GT und GG zuzuordnen. Im Bereich 500–390 cm −1 befindet sich ein “Konformerenfenster”, das die eindeutige Identifikation der vier Konformeren gestattet.

Far-infrared spectra of the ammonia and hydrogen forms of zeolites of types X and Y

Far-infrared spectra of the zeolites NH4NaX, NH4NaY, HNaX and HNaY at various degrees of exchange and of their dehydroxylated forms have been measured, and the preferred positions of NH+4 within the zeolites have been estimated. The expected bands corresponding to cation motion of H+ or vibrations of hydrogen-bridged OH groups were not detected in the spectra of either the HNaX or HNaY zeolites. Conclusions concerning the arrangement of cations in the zeolites are based on the results of our f.i.r. spectra and on the X-ray diffraction results of other authors for alkali-metal-exchanged zeolites.

Zum konformationsverhalten einiger halogenalkane

Abstract The rotational isomerism of 1-bromopropane, 1-chloro-2-methylpropane and 1-bromo-2-methylpropane has been studied in the liquid phase by infrared spectroscopy. For the corresponding conformers the enthalpy differences were obtained from the temperature dependences of the intensities of the CX-stretching and some CCC-deformation vibrations. It was found that only the CX-stretching vibrations are suitable for enthalpy determinations. In the liquid phase those conformers with a gauche position of the methyl group and halogen atom are slightly preferred.

Das schwingungsspektrum des CH3OSO2Cl

Abstract Infrared and Raman spectra have been recorded for liquid CH 3 OSO 2 Cl, also the i.r. spectra of the vapour and of solutions in CCl 4 . With exception of the two torsional modes, all fundamentals were observed and assigned on the basis of symmetry C inS (staggered H … O conformation). Calculation of force constants and of potential energy distribution have been carried out.

Über das assoziationsverhalten der syn- und anti-isomeren aliphatischer aldoxime☆

Abstract The association of the syn - and anti -isomers of n -heptane aldoxime and n -decane aldoxime was studied by infrared spectroscopy. It has been found that in carbon tetrachloride the anti -isomers are much more strongly associated than the corresponding syn -isomers. The reason for this behaviour is the different acceptor strength of the NOH-group in the isomers as could be confirmed by NMR-studies of oxime solutions in presence of europium(III)-acetyl-acetonate as shift reagent. The results agree with those from earlier normal coordinate treatments.