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[reaction: see text] 5,10,15,20-Tetrakis(m-hydroxyphenyl)porphyrin (m-THPP) yielded novel quinonoid porphyrins upon irradiation in aqueous methanol. True photobleaching was observed for 5,10,15,20-tetrakis(m-hydroxyphenyl)chlorin (m-THPC) and 5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin (m-THPBC) under the same conditions; several fragmentation products (imides, methyl p-hydroxybenzoate, dipyrrin derivatives) were recognized. 相似文献
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PHOTOPHYSICAL PROPERTIES OF meso-TETRAPHENYLPORPHYRIN and SOME meso-TETRA(HYDROXYPHENYL)PORPHYRINS 总被引:3,自引:0,他引:3
R. Bonnett D. J. McGarvey A. Harriman E. J. Land T. G. Truscott U-J. Winfield 《Photochemistry and photobiology》1988,48(3):271-276
Abstract— The o-, m-, and p-isomers of 5, 10, 15, 20- tetra(hydroxyphenyl)-porphyrin have been of recent interest as potential second-generation sensitisers in tumour phototherapy. Fluorescence spectroscopy, nanosecond laser flash photolysis and pulse radiolysis have been used to characterise the singlet and triplet excited states of tetraphenylporphyrin and the o, m-, and p-isomers of tetra(hydroxyphenyl)porphyrin. This has included evaluation of fluorescence yields and lifetimes, triplet spectra, lifetimes, oxygen quenching rate constants, extinction coefficients, and yields and singlet oxygen yields. Whilst the fluorescence quantum yields were low, the triplet yields were all 0.7 ± 10% and the singlet oxygen yields 0.6 ± 10%: all these parameters are in the ranges shown by other efficient porphyrin photosensitisers. The similar photophysical properties found for these compounds suggest that their differing tumour sensitising efficiencies are likely to be due to other factors. 相似文献
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Far-infrared laser magnetic resonance spectra of NHD (X 2A′') (0,0,0) have been observed. Data are presented for the rotational transitions 313 ← 202 and 413 ← 322 observed at wavelengths of 211.3 and 374.1 μm respectively. Theoretical values of the transition magnetic field strengths have been calculated using the best available molecular constants. The agreement between theory and experiment confirms our spectroscopic assignments, but indicates that with further experimental data, considerable refinement of the molecular constants will be obtained. 相似文献
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Richard Bonnett Robert G. Guy David Lanigan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):95-103
Abstract Thiocyanogen reacts slowly with alkenes, in the presence of a radical inhibitor in benzene or acetic acid in the dark at 25°, to yield α,β-dithiocyanates, α-isothiocyanates-β-thiocyanates and, in acetic acid, α-acetoxy-β-thiocyanates in varying proportions. The additions to alkyl alkenes are trans-stereospecific, and, in the case of the α-isothiocyanato-β-thiocyanates, non-regiospecific. The additions to aryl alkenes are trans-stereoselective and regiospecific, yielding the Markownikov-orientated α-isothiocyanato-β-thiocyanates. A heterolytic mechanism involving a two-step, kinetically controlled addition, with the formation of a cyano-sulfonium ion intermediate, e.g., 35, in the case of alkyl alkenes and an open carbonium ion, e.g., 36, in the case of aryl alkenes, is suggested. The diothiocyanate: isothiocyanato-thiocyanate ratios are discussed in terms of kinetic and steric control of reaction. 相似文献
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Bonnett PE Carpenter KJ Dawson S Davey RJ 《Chemical communications (Cambridge, England)》2003,(6):698-699
In many situations the process of crystallisation from solution is known to occur via metastable crystalline states (polymorphs or solvates). Here we present what we believe to be a novel example of small molecule crystallisation in which the initial separation of a solute rich liquid phase precedes the crystallisation event. We believe this occurs because a submerged liquid-liquid phase boundary is accessible within the metastable zone of the crystal nucleation process. 相似文献
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J. K. Brooks Kazuyuki Saitô JD Maitland Wright 《Rendiconti del Circolo Matematico di Palermo》2003,52(1):5-14
LetA be aC*-algebra with second dualA″. Let (φ
n)(n=1,...) be a sequence in the dual ofA such that limφ
n(a) exists for eacha εA. In general, this does not imply that limφ
n(x) exists for eachx εA″. But if limφ
n(p) exists whenever p is the range projection of a positive self-adjoint element of the unit ball ofA, then it is shown that limφ
n(x) does exist for eachx inA″. This is a non-commutative generalisation of a celebrated theorem of Dieudonné. A new proof of Dieudonné’s theorem, for
positive measures, is given here. The proof of the main result makes use of Dieudonné’s original theorem. 相似文献
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Zeeman spectral data are presented for the 2Π3/2: J = 7/2 → J= 9/2,2Π3/2: J= 7/2→2Π1/2:J= 5/2 and2Π3/2 J= 3/2→ J = 5/2 transitions in OD. Data for the 2Π3/2. J=3/2→ J= 5/2 and 2Π3/2 J= 5/2 → 2Πl/2 : J= 3/2 transitions in OH, taken under similar conditions, are included. 相似文献
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