Composition of the basic fraction of marijuana and tobacco condensates: A comparative study by capillary GC/MS

Summary Combined capillary gas chromatography/mass spectrometry has been used to characterize the basic fraction of Mexican marijuana and standard tobacco smoke condensates. A thermostable Superox-coated glass capillary column permitted elution of relatively large nitrogen-containing compounds. Substantial qualitative and quantitative differences between the two materials were noted.Dedicated to Dr. L. S. Ettre on the occasion of his 60th birthday.     

Single-crystal structures of polyphenylene dendrimers

A series of first-generation polyphenylene dendrimers based on three different cores were prepared by Diels-Alder cycloaddition and their single-crystal structures were determined. Consisting exclusively of interlocked, twisted phenyl rings, these polyphenylene nanostructures have exciting structural and dynamic properties. Single crystals of dendrimers, suitable for X-ray structure analysis, were grown from different solvent mixtures by slow evaporation at room temperature. It should be pointed out that one of the described polyphenylene dendrimers represents up to now the biggest oligophenylene nanostructure from which crystallographic data is available.     

On the connection between the inverse transform method and the exact quantum eigenstates

The “inverse scattering transformation”, which has been used to solve certain non-linear field theories classically, is discussed in the context of the quantized version of these theories. In particular we consider the non-linear Schrödinger equation and the massive Thirring model. We find that certain Jost functions of the associated scattering problem lead already, in quantizing the theory, to creation operators for the exact eigenstates of the corresponding Hamiltonians.     

High-efficiency microcolumn separation of polycyclic arene isomers isolated from carbon black

Summary A packed capillary LC column, featuring 225,000 theoretical plates, was used to resolve numerous polyaromatic isomers (six to nine-ring structures) from an extract of carbon black. Although mass-spectral investigations carried out on the trapped components provide ony tentative identification of large aromatic molecules, improved isomeric resolution through the use of LC microcolumns is a signjifiocant improvement over hitherto used-methods.Dedicated to Profesor A. Zlatkis on the occasion of huis 60th birthday.     

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Ohne Zusammenfassung     

Polyphenylene dendrimers with different fluorescent chromophores asymmetrically distributed at the periphery

A new synthetic approach leading to asymmetrically substituted polyphenylene dendrimers is presented. Following this method, polyphenylene dendrimers decorated with an increasing number of chromophores at the periphery have been obtained up to the second generation. Especially the synthesis of a polyphenylene dendrimer bearing three donor chromophores and one acceptor chromophore has been realized. Intramolecular energy transfer within this molecule is demonstrated by applying absorption and fluorescence measurements.