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We give a self‐contained proof of the preservation theorem for proper countable support iterations known as “tools‐preservation”, “Case A” or “first preservation theorem” in the literature. We do not assume that the forcings add reals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Palladium(II)-catalyzed oxidations constitute a paramount reaction class but have remained immature over the past few decades. Recently, this field has reappeared at the forefront of organometallic catalysis. This emerging area article outlines recent developments in palladium(II)-catalyzed oxidation chemistry with discussion of potential future growth. 相似文献
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The molecular structure of 4,4′-sulfanidyl-bis-thiophenol (C12H10S3) has been determined by gas electron diffraction. Assuming identical geometry and D2h local symmetry for ---SC6H4S--- moieties, the following bond lengths (rg) and bond angles were obtained: C---H = 1.101 ± 0.005, S---H = 1.388 ± 0.019, (C---C)mean = 1.400 ± 0.003, (S---C)mean = 1.778 ± 0.004 Å, Car---S---Car = 103.5 ± 1.3, C---C(S)---C = 120.4 ± 0.3, C(H)---C(H)---H = 119.1 ± 0.9 and C---S---H = 94.6 ± 3.1°. Two ratational forms were found to reproduce the experimental data, characterized by dihedral angles of the benzene rings with respect to the CarSCar plane; 1 = 67.8 ± 2.0°, 2 = 4.5 ± 7.2°, and 1 = 69.4 ± 2.0δ, 2 = −26.6 ± 7.1°. Identical signs of 1 and 2 indicate that the two benzene rings are rotated in the same direction about the respective Scentral---C axes. 相似文献
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The synthesis of N-methyl-benz[f]isoindole ( 2 ) and N-methyl-dibenz[e,g]isoindole ( 3 ) is reported. The NMR. spectra of N-methyl-isoindole ( 1 ) and of 2 have been analysed and the implications concerning the alternation of bond lengths are discussed. The photophysical properties of 1 to 3 have been investigated by the following methods: HeI photoelectron (PE.) spectroscopy, UV./VIS. absorption (polarization measurements by the stretched-foil technique) and emission spectroscopy (fluorescence spectra, lifetimes and quantum yields, phosphorescence spectra), and flash spectroscopy (triplet-triplet absorption spectra). The discussion of the results is based on HMO. and PPP SCF CI. calculations and points to the relationship between the heterocycles 1 to 3 and the corresponding benzenoid hydrocarbons obtained by replacement of the ? NMe? subunit by ? CH?CH? . Some comments concerning the ground state properties of isoindole and related compounds are derived from the analysis of their electronic structure. 相似文献
10.
Jan F. Keij Jan Th . M. Jansen Frank W. Schultz Jan W. M. Visser 《Photochemistry and photobiology》1994,60(5):503-509
Abstract-During the development of a photodamage cell sorter several photosensitizers were tested for their ability to photoinactivate more than 90% of the sensitized cells after a brief irradiation with a fluence of 10 kJ/m2 . In pilot experiments, yeast cells sensitized with 10-dodecyl acridine orange (DAO) were effectively photoinactivated after receiving a fluence of 10 kJ/m2 delivered in 8 s. However, when the same fluence was delivered in 3 μ s during passage through a focused laser beam in the cell sorter, all cells survived.
Computer simulations of the relevant photophysical and chemical reactions inside the irradiated cell were used to investigate the cause of this phenomenon. The results indicated that the absence of photoinactivation by DAO, after flash irradiations, was caused by the combined effects of (1) limited oxygen diffusion into the cell and (2) a reduced number of collisions between photosensitizer triplet and oxygen molecules during the irradiation due to saturation of the intracellular photosensitizer triplet concentration. The contributions of triplet-triplet annihilation and triplet quenching by ground state photosensitizer molecules were found to be minimal and not significant. These findings indicate that Type II photosensitizers are incapable of rapid selective photoinactivation in cell sorters. 相似文献
Computer simulations of the relevant photophysical and chemical reactions inside the irradiated cell were used to investigate the cause of this phenomenon. The results indicated that the absence of photoinactivation by DAO, after flash irradiations, was caused by the combined effects of (1) limited oxygen diffusion into the cell and (2) a reduced number of collisions between photosensitizer triplet and oxygen molecules during the irradiation due to saturation of the intracellular photosensitizer triplet concentration. The contributions of triplet-triplet annihilation and triplet quenching by ground state photosensitizer molecules were found to be minimal and not significant. These findings indicate that Type II photosensitizers are incapable of rapid selective photoinactivation in cell sorters. 相似文献