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131.
Wieslaw Wojnowski Barbara Becker Karl Peters Eva-Maria Peters Hans Georg von Schnering 《无机化学与普通化学杂志》1987,553(10):287-292
Structure of Pentaphenyldisilane For the first time Pentaphenyldisilane was prepared by Gilman and Goodman. It is produced by the reaction of Ph3SiLi with Ph2ClSiH. The crystal structure presents an ideally staggered conformation. The distance d(Si? Si) = 235.7 pm corresponds to a normal single bond length. This emphasizes the complete relief of the central Si? Si bond by the insertion of only one hydrogen atom. 相似文献
132.
VNCl2(Pyridine)2; Synthesis, I. R. Spectrum, and Crystal Structure VNCl2(Pyridine)2 is formed from the cyclothiazeno-vanadium(IV) complex [VCl(N3S2)(Pyridine)2]2 · 2 CH2Cl2 in boiling toluene in form of brown-red, hydrolysis sensitive crystal. It was characterized by its I.R. spectrum and an X-ray crystal structure determination. VNCl2(Pyridine)2crystallizes in the orthorhombic space group Pccn with four formula units per unit cell (668 observed independent reflexions, R = 0.055). Lattice constants: a = 1550, b = 924, c = 832 pm. Monomer molecules are situated on twofold rotation axes. They are stacked along the V?N axis to form columns V?N…V. The short VN bond of 160 pm corresponds to a triple bond, whereas the V…N distance of 256 pm indicates a weak interaction. The V? N(Pyridine) and V? Cl bond lengths are 213.0 and 233.5 pm, respectively. 相似文献
133.
The phytochemical investigation of the dried fruits of Swartzia madagascariensis (Leguminosae) afforded the five triterpenoid saponins 1–5 . They were shown to be glucuronides of oleanolic acid and of gypsogenin by chemical and spectral means ( FAB-MS , 13 C-NMR , GC / MS ). One of the isolated compounds, identified as 3-O-[O-α-L-rhamnopyranosyl-(1→3)-(β-D-glucopyranosyluronic acid)]oleanolic acid, was responsible for the high molluscicidal activity of Swartzia madagascariensis fruits against the schistosomiasis-transmitting snails Biomphalaria glabrata and Bulinus globosus. 相似文献
134.
Ion-selective electrodes based on the neutral carrier, 12-crown-4, in a poly(vinyl chloride) matrix were found to respond ideally, or almost ideally, to potassium, sodium, barium, strontium, magnesium, cobalt(II), nickel(II) and aluminum ions. The electrode showed good selectivity for Al3+ over Co2+ and Mg2+, and for Co2+ over Mg2+. Little selectivity was found for the other ions tested. 相似文献
135.
Jieping Wang Norbert Moszner Kurt Dietliker Hansjörg Grützmacher Robert Liska 《Journal of polymer science. Part A, Polymer chemistry》2016,54(4):473-479
The monoacylphosphineoxide (MAPO) salts Na‐TPO and Li‐TPO and the bisacylphosphineoxide (BAPO) salts BAPO‐ONa and BAPO‐OLi define an important and in the latter case a new class of water‐soluble photoinitiators (PIs) for radical polymerization. These compounds showed excellent water‐solubility of at least 29 g/L for Na‐TPO and up to 60 g/L for BAPO‐ONa in deionized water, thus exceeding the solubility of the state of the art PI for water‐based systems Irgacure 2959 ( I2959 ) 6‐ to 12‐fold. However, biocompatibility, storage stability, and reactivity were equally important to replace the state of the art compounds. Concerning these properties, the MAPO and BAPO salts were at least in the same range (biocompatibility, stability) or showed even better results (reactivity) and had the additional advantage of visible light initiation. Na‐TPO and Li‐TPO achieved double bond conversions of an aqueous solution of N‐acryloylmorpholine over 97% with broad band irradiation (320–500 nm), Li‐TPO showed additionally very good biocompatibility (LC50 = 3.1 mmol/L) and BAPO‐OLi showed highest reactivity with visible light irradiation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 473–479 相似文献
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138.
Rodger D. Scurlock Christopher H. Evans Silvia E. Braslavsky Kurt Schaffner 《Photochemistry and photobiology》1993,58(1):106-115
The mechanism of I700 decay, representing an early event in the phytochrome Pr→ Pfr phototransformation, was reanalyzed in the microsecond range by conventional laser flash photolysis as well as by two-laser/two-color flash photolysis. Three kinetic models that might describe the I700 decay mechanism following Pr excitation were considered: a parallel, a sequential, and an equilibrium model. These models were used to mathematically simulate both the one- and two-laser flash experiments in an effort to select the model best describing the I700 decay. The sequential model could be excluded already on the basis of the one-laser flash photolysis results alone. Discussion of the two-laser/two-color flash rcsults in the context of the equilibrium and the parallel models is presented. 相似文献
139.
Peter Lindemann Silvia E. Braslavsky Marie-Michle Cordonnier Lee H. Pratt Kurt Schaffner 《Photochemistry and photobiology》1993,58(3):417-424
Abstract–Thc kinetics of the microsecond phototransformation intermediates of 124 kDa Avena phytochrome (17001,2) were studied in the prcsence of bound monoclonal antibodies at various temperatures. A global analysis was applied to the decays at all wavelengths at each temperature in order to derive the rate constants and the decay-associated spectra of the three decay components. Monoclonal antibodies bound to specific epitopes altered the Arrhenius parameters of both 17001,2 decay components. The strongest influence on these parameters was observed with OAT 8 (epitope between residues 624 and 686), which decreased by more than 50% the activation parameters of both components. This decrease is interpreted to result from an increased flexibility induced by this antibody in the ground state or in the transition state of bonds changing during the decay of both 1700 transients. Thus, the OAT 8 cpitope appears to be functionally important during the decay of the 17001,2 intermediates. For the case of 11001 bound OAT 23 and OAT 25 (epitopes between residues 1 and 66) reduced even further the relatively small flexibility of these bonds in the red light-absorbing form of phytochrome (P1) without antibodies, as reflected by the high preex-ponential factors for its decay. This resulted also in higher activation energies for this decay in the presence of the antibodies. Thus, the amino-terminus should act as a rigid spacer of the chromophore cavity without affecting it during the microsecond transformation, because the Arrhenius parameters for these decays are similar to those for small phytochrome. The possible implications of the influence of the various antibodies on the bleaching remaining after the decay of 17001,2 are discussed. 相似文献
140.