Gerhard Geiseler

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.

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.

Normalschwingungen substituierter Harnstoffderivate

The ir spectra of solid N-acetyl- (MAH), N,N′-diacetyl- (DAH) and bis[N-methyl-N-acetyl]urea (BMAH) were recorded in the range 4 000–400 cm−1 and of N,N′-dimethylurea (DMH) in the range 4 000–100 cm−1. The vibrational assignments of these compounds and of N-methylurea (MMH) are given by normal coordinate analysis on the basis of the GF matrix method. The force field adopted in the calculation is the local symmetry force field (LSFF). The force constants were adjusted by a least-squares method to get a better agreement between the observed and calculated wavenumbers for the well known monosubstituted derivatives. The same force constants without further adjustment were used to calculate the wavenumbers and potential energy distributions ofDMH,DAH andBMAH. One of the main interests in these studies lies in the examination of the amide and imide characteristic vibrations because of their importance in the field of biochemistry.

Einfluß der Kettenlänge auf die intensität charakteristischer CX-valenzschwingungen unverzweigter 1-substituierter alkanderivate☆

Abstract The influence of the chain length on the intensity of characteristic valence vibrations of unbranched 1-halogen-and 1-nitrilo-alkanes has been studied. It is found, that the intensities of the C-hal-vibration for the gauche conformers reach a boundary value at chain length above six carbon atoms in agreement with other inductive properties. The CN-vibration, which is not split by rotation isomerism, behaves similarly. The corresponding intensities of the trans conformers, however, point out a distinguished maximum at chain length of six carbon atoms. The behaviour is obviously caused by interaction between the substituent and the alkyl group. On the basis of the field effect and the Taft-relation a theoretical interpretation is given.

Dipolmomente stellungsisomerer Alkanderivate

ZusammenfassungDie Dipolmomente der sich vom n-Octan ableitenden stellungsisomeren Fluoride, Chloride, Bromide, Jodide, Alkohole, Nitrile, Carbonsäuren und Nitroverbindungen wurden nach der Methode vonGuggenheim undSmith ermittelt. Aus den Ergebnissen folgt, daß offensichtlich die in bezug auf das Wasserstoffatom elektronegativen Substituenten das Dipolmoment erhöhen, wenn sie vom Kettenende in die Molekelmitte rücken. Umgekehrt verhalten sich die elektropositiven Substituenten. Bei den Fluoriden, Alkoholen und Carbonsäuren zeigt sich außerdem ein ausgeprägt alternierender Gang.AbstractThe dipole moments of all position isomeric fluorides, chlorides, bromides, iodides, alcohols, nitriles, carboxylic acids and nitro compounds derived from n-octane have been determined by theGuggenheim-Smith method. The results show an increase of dipole moments by substituents electronegative in relation to hydrogen atoms in the order mid-chain positions → end-chain positions. Electropositive substituents have the inverse effect. Fluorides, alcohols and carboxylic acids show alternating increase and decrease.