Über ungesättigte Monocyclen mit durchlaufender Konjugation, 1. Mitt.

Ohne Zusammenfassung     

Quantenmechanische und photophysikalische Untersuchungen zum Termschema von Acechinonen

Ohne Zusammenfassung     

Raumsparende Darstellung von Moleküldiagrammen bei vergleichenden quantenchemischen Untersuchungen

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Band structure of nonclassical polymers

It is shown that fully conjugated alternant nonclassical polymers are comparatively stable systems as a result of the considerable delocalisation energy.The energy characteristics of the polymers are strongly determined by the electron spin distribution of the degenerate nonbonding molecular orbitals; the full spin configuration,S>0, is favoured. The spin densities depend on the electron correlation and alternate; this corresponds to a ferrimagnetic state of the polymer at 0°K.     

On the floating basis set model for studying the vibronic interaction in polyatomic molecules

The floating basis set model by Johnson and Weigang is reinvestigated using a general picture of the molecular hamiltonian. It is found that Johnson and Weigang, though considering explicitly that electrons move with the nuclei, ignored a contribution to the electronic wavefunction from the coupling of the vibrational and electronic motions of the electrons. The vibrational wavefunctions and energies of the molecule are also modified.     

1,4-Photoaddition of maleic anhydride to chrysene

The photoDiels-Alder reaction of maleic anhydride with chrysene yields chryseno[4,5-efg]isobenzofuran-4,6-dion (VI). Heavy atom experiments using xenon as an external perturber show that the reaction occurs via the lowest singlet excited state of chrysene. Hydrogen is abstracted from the primaryDiels-Alder adduct IV by the solvent CH₂Cl₂ possibly in a two-step mechanism. The reaction presents a new type of photoreaction, its mechanism possibly follows a scheme not considered so far in photochemistry.

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1,4-Photoaddition von Maleinsäureanhydrid an Chrysen

Zusammenfassung Die Photo-Diels-Alder-Reaktion von Maleinsäureanhydrid mit Chrysen ergibt Chryseno[4,5-efg]-isobenzofuran-4,6-dion (VI). Schweratomexperimente mit Xenon als äußerer Störer zeigen, daß die Reaktion vom niedrigst angeregten Singulettzustand des Chrysens ausgeht. Die Abstraktion von Wasserstoffatomen aus dem primärenDiels-Alder-Addukt IV durch das Lösungsmittel CH₂Cl₂ folgt möglicherweise einem Zweistufenmechanismus. Die Reaktion stellt einen neuen Typ von Photoreaktion dar; möglicherweise folgt sie einem Mechanismus, der in der Photochemie neuartig ist.

     

Bi2223带材临界电流沿长度方向的统计分布

本文采用四引线法测量了Bi2223带材临界电流沿长度方向的分布,采用正态分布、对数正态分布、威布尔分布和最小极值分布对临界电流分布进行了拟合检验,确定了临界电流的最优统计分布模型.     

4,5-Dihydro-5-thioxo-]H-tetrazoie-l-alkanoic and alkanesulfonic acids and their amide derivatives

Homologous 4,5-dihydro-5-thioxo-1H-tetrazole-l-alkanoic and alkanesulfonic acids were prepared by reaction of sodium azide with methyl (carboxyalkyl)- and (sulfoalkyl) carbamodithioates, respectively. 4,5-Dihydro-5-thioxo-1H-tetrazole-i-alkanamides were derived from the corresponding alkanoic acids by aminolysis of their acid chlorides or imidazolides. Analogous alkane-sulfonamides were synthesized by the reaction of methyl [[[(1,1-dimethylethyl) amino]sulfonyl]-alkyljcarbamodithioates with sodium azide followed by removal of the 1,1-dimethylethyl group with trifluoroacetic acid.