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101.
Ruedi Gygax Jakob Wirz Joseph T. Sprague Norman L. Allinger 《Helvetica chimica acta》1977,60(8):2522-2529
The isodynamical interconversion between the quasiplanar equilibrium conformers 1b and 1c of 1,5-bisdehydro[12]annulene requires a free energy of activation ΔG# = 4.5 ± 0.2 kcal/mol (120 K) which was determined by line shape analysis of its temperature-dependent NMR. spectrum. Force field calculations indicate that this barrier reflects the energy needed to disrupt the cyclic π-conjugation in going to the nonplanar transition state 1a . 相似文献
102.
Bernd Klingert Achim Roloff Bernhard Urwyler Jakob Wirz 《Helvetica chimica acta》1988,71(8):1858-1867
Laser flash photolysis and matrix-isolation techniques were applied to elucidate the photochemistry of the orange complex bis(pentafluorophenyl)titanocene ( = bis(η5-cyclopentadienyl)bis(pentafluorophenyl)titanium- (IV), Cp2TiIV{C6F5}2, Cp = η5-C5H5, 1 ) which is used as a polymerization photo-initiator. The primary photo-reaction of 1 is the formation of a highly reactive blue isomer X with unit quantum yield. In carefully dried and degassed benzene solution, the photoisomer X rearranges to starting material 1 with a first-order reaction, k = 5 · 103 s?1 at room temperature. X is highly reactive towards H2O, MeOH, acetone, MeCN, MeNO2, butane-1,4-diyl diacrylate, 2,2,6,6-tetramethylpiperidine N-oxide, CO, O2, and N2; absolute bimolecular rate constants range from 106 to 109 M ?1 · s?1. The primary photoisomerization 1→X is tentatively ascribed to a cyclopentadienyl ring slippage from η5 to a lower hapticity, a process that opens up coordinative unsaturation. 相似文献
103.
104.
J.P. Bondorf 《Nuclear Physics A》1973,202(1):30-36
The difference between the observed fluctuations in the elastic excitation functions for carbon-carbon and oxygen-oxygen scattering, just above the Coulomb barrier, is interpreted in terms of the compound nucleus model. 相似文献
105.
106.
Jakob P. Bondorf Philip J. Siemens Sten Garpman E. C. Halbert 《Zeitschrift für Physik A Hadrons and Nuclei》1976,279(4):385-394
We consider heavy-ion collisions with beam energies of a few hundred MeV/nucleon, because such collisions seem favorable for producing compressed nuclear matter. As an alternative to hydrodynamic ways of calculating such collisions, we are investigating a microscopic, rapid (and therefore economical) simulation method. There are two simplifications basic to this method: (i) using classical particle kinematics, and (ii) taking nucleonnucleon interactions into account via cross sections rather than explicit forces. Some other simplifications, concerning nuclear binding etc., are presently crude but will be improved. Even at normal density, nuclear matter is not so dilute; therefore our calculations show some sensitivity to details of the mechanism assume for nucleon-nucleon scattering. For head-on collision of two mass-235 nuclei, our present calculations yield maximum densities between 2 and 3 times that of normal nuclear matter. 相似文献
107.
108.
Near UV. irradiation of N-methyl isoindole ( 1 ) in deaerated solution has yielded two constitutionally isomeric [π4s+π4s] dimers 3 and 4 (Scheme 2). No transient or stable photoisomers of 1 were detected. The photodimers were reconverted to 1 both by pyrolysis and photolysis. The photocleavage of dimer 3 proceeds (predominantly) by anonadiabatic pathway yielding 1 in its electronic ground state. Prolonged pyrolysis of 1 afforded 11H-indeno [1,2-c]-isoquinoline ( 5 ) as a major product. 相似文献
109.
Karl Jakob Dienst 《Geometriae Dedicata》1977,6(1):23-53
Ohne ZusammenfassungHabilitationsschrift Darmstadt 1975. 相似文献
110.
Karl Jakob Dienst 《Journal of Geometry》1974,5(1):67-81
If is a projective space of dimension 3 and characteristic 2 and a semi ovoid of, then is a non degenerate semi quadric and is of finite dimension, if and only if there exists a perspectivity of order 2 and axish stabilizing, for every hyperplaneh meeting in at least 2 points. 相似文献