Mechanisms of mass spectrometric fragmentations: X–Interaction between remote or-groups in decalin-1,5-diols and their dimethyl ethers

The mass spectra of the five stereoisomers of decalin-1,5-diol and its dimethyl ether have been investigated. The differences in the mass spectra of stereoisomers I to III with a trans- decalin ting system are small. The differences are much larger in the mass spectra of the two isomers IV and V of the cis-decalin series and the elimination of CH₂O, formed by interaction between the two methoxy groups, from the molecular ion is only observed in the mass spectrum of Vb.     

Dielectric Properties of Apolar Micelle Solutions Containing Solubilized Water

Varying amounts of water have been solubilized in a micelle solution of sodium di-2-pentyl–sulfoscuccinate in benzene and the complex permittivity has been observed in the range 200 KHz to 10 MHz. Part of a dielectric dispersion is seen, which extends to higher frequencies with a broad distribution of relaxation times. Due to association processes, the static dielectric increment is found to vary non-linearly with hydrated micelle concentration and with the amount of solubilized water, whereas a linear variation with micelle concentration is found if no water is added. These effects are explained on the assumption that part of the solubilized water increases the dipole moment of the micelle. Additionally, at higher water concentrations, a sudden increase in the conductivity of the solution is observed, which is taken to indicate a conformational change of the solubilized micelle.     

Einelektronen-Redoxreaktionen von 4-(1-Pyridinio)phenolat-Betain: ESR/ENDOR-Charakterisierung seiner Radikalionen und ‘Batterie-Effekt’

One-Electron Redox Reactions of 4-(1-Pyridinio)phenolate Betaine: ESR/ENDOR Characterization of its Radical Ions and ‘Battery Effect’ Blue zwitterionic 2,6-Di(tert-butyl)-4-(2,4,6-triphenyl-1-pyridinio)phenolate 1a can be reduced to its blue-green radical anion ${\bf 1}^{- \atop \dot{}}$ using alkaline metals, and oxidized to its colorless radical cation 1 by Ag(OOCCF₃) or electrochemically. ESR/ENDOR spectra of their aprotic THF solutions indicate predominant spin population either in the pyridinium (${\bf 1a}^{- \atop \dot{}}$) or in the phenolate ring (${\bf 1a}^{+ \atop \dot{}}$). Reduction with other alkaline metals Li, Na, or Cs yields no changes in the ESR/ENDOR signal patterns, i.e. provides no indication of radical ion pair formation. The cyclovoltammetrically determined first reduction and oxidation potentials at ?1.11 V and +0.26 V, respectively, are both reversible and, in principle, allow to construct a molecular battery.     

Electrical properties of planar bimolecular surfactant membrane

Planar bimolecular film of the triple long-chain salt(dihexadecyldimethylammonium hexadecanesulfonate) was found to be formed in the electrolyte solutions was carried out at different temperatures by the transient D. C. method. In four electrolyte solutions of Li⁺, Na⁺, K⁺, and Cs⁺ chlorides, the resistance of the membrane was very high (up to 10⁷ ohm·cm²). From the temperature-dependence of conductivity, the activation energy of ion transfer through the film was calculated by the Arrhenius equation. The magnitude of the activation energy was related with the size of the crystallographic radius.The authors acknowledge financial support from the Swiss National Science Foundation.     

Methylcobaltverbindungen mit nicht chelatisierenden Liganden,IV. Monoolefinkomplexe

Methylcobalt Compounds with Non-chelating Ligands, IV. Monoolefin Complexes Tris(trimethylphosphane)cobalt(I) halides in ether solvents saturated with olefin at low temperatures from monoolefin complexes which are prone to dissociation. Upon reaction with methyl-or phenyllithium more stable compounds are formed of the composition CoR(CC)L₃ ( 1 – 4 ) (R  CH₃; CC  C₂H₄, C₃H₆, cyclo-C₅H₈; R  C₆H₅; CC  C₂H₄; L  P(CH₃)₃). In solution the fluctional molecules adopt a ground state structure containing a σ-bonded group and an olefin ligand in adjacent positions (trigonal-bipyramidal: CH₃ axial and C₂H₄ equatorial or C₆H₅ and C₂H₄ equatorial). The latter arrangement is confirmed for the crystalline state by an X-ray structure determination of (ethene)phenyltris(trimethylphosphane)cobalt ( 4 ). An equatorial plane of coordination along a Co P bond not only contains both ethene-C atoms but also all the atoms of the phenyl group. The compound is thermally decomposed to give biphenyl and (ethene)tris-(trimethylphosphane)cobalt(0). No products of an olefin insertion reaction are observed.     

Synthesis,structure, and X-ray absorption spectra of LixNbO2 and NaxNbO2 (x ≤ 1)

The two series of compounds, Li_xNbO₂ and Na_xNbO₂, were synthesized from LiNbO₂ and NaNbO₂ with oxidizing agents. From neutron diffraction, it is concluded that the Li position is fully occupied for x = 1. Even though the long-range crystal symmetry does not seem to change for x < 1, as monitored by Guinier X-ray powder patterns, the Nb? L_III XANES spectra exhibit significant spectral variations with x which reflect changes in the unoccupied d-density of states.