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111.
Edward R. T. Tiekink Tomas Kurucsev Bernard F. Hoskins 《Journal of chemical crystallography》1989,19(5):823-839
The preparation, characterization, and X-ray structure analysis of (adeninatoN9)triethylphosphinegold(I) is reported. The crystal structure consists of discrete molecules, the adeninate anion coordinates via the N(9) atom with a Au-N(9) bond distance of 2.057(5) Å and the linear geometry about the Au atom is completed by the P atom of a disordered Et3P ligand; the Au-P(1) bond distance is 2.238(2) Å and the N(9)-Au-P(1) bond angle is 178.8(2)°. The crystals are orthorhombic, space groupPbca, with unit cell dimensionsa=8.528(1),b=17.797(3),c=18.526(2) Å andZ=8. The structure was refined by a full-matrix least-squares procedure to finalR=0.030 andR
w
=0.033 for 1749 reflections withI>2.5a(I). The electronic spectrum of the complex dissolved in water in the near ultraviolet is consistent with essentially separate -electron systems of the adenine and phosphinegold moieties; a conclusion which corroborates the X-ray structural results. 相似文献
112.
Edward B. Manoukian 《International Journal of Theoretical Physics》1989,28(5):501-510
Explicit solutions are derived for transition amplitudes associated with stimulated emission of relativistic particles by external sources inspacetime. More precisely, exact expressions are obtained for transition amplitudes for any process where there are initially, at a given time, an arbitrary number of particles localized in various regions of space, prior to the switching on of an intervening source, and then, finally, at a later time when the intervening source ceases to operate, a given number of particles are found to be localized in various regions of space. The analysis is given for massive particles ofarbitrary integer and half-integer spins. The solutions are obtained by carrying out a unitarity expansion inconfiguration space, where particles travel between emitters and detectors in the presence of an intervening source. Considered as an application is the process: particlearbitrary number of particles, where the latter particles emerge spatially with a cone. 相似文献
113.
Edward B. Manoukian 《International Journal of Theoretical Physics》1989,28(5):495-499
The problem of stimulated emission of photon excitations by external currents is studied inspacetime by making use of the concept of localized photon excitations in configuration space. An explicit expression is derived for the amplitude that an arbitrary number of photon excitations are produced and found in arbitrary localized regions in space when there are an arbitrary number of photon excitations prior to the switching on of the intervening current. Considered as an application is the reaction of a photon splitting to any number of photon excitations as the latter emerge spatially within a cone in the presence of a strong external electromagnetic current. This work is a generalization of work dealing with strictly massive particles. 相似文献
114.
Gajdek P Bober B Mej E Bialczyk J 《Journal of photochemistry and photobiology. B, Biology》2004,76(1-3):103-106
UV radiation was applied to degrade cyanobacterial hepatotoxin, microcystin-LR in the presence of phycocyanin as a model natural sensitiser. The concentrations of both the toxin and the pigment used in the experiments were higher by several orders of magnitude than found in the environment. The photoreaction parameters were optimised. The process was found to be of limited use for water treatment due to its low efficacy. Additionally, pronounced UV-induced bleaching of the pigment significantly reducing the photoreaction rates of the toxin was observed for the highest UV radiation intensities applied. 相似文献
115.
An ionic form of diphenyltrichlorophosphorane, namely, diphenyldichlorophosphonium trichloride isolated as a dichlorine solvate (1), was obtained by treating PPh(2)Cl(3) with excess chlorine. The identity of this species was established by single-crystal X-ray analysis and (31)P, (1)H, and (35)Cl NMR and Raman spectra. Bis(diphenyldichlorophosphonium) pentachloroindate (2) was obtained by the reaction of diphenyltrichlorophosphorane with indium trichloride in dichloromethane for comparison purposes. Its identity was determined by (31)P NMR spectra and single-crystal X-ray analysis. 相似文献
116.
A new algorithm/program has been elaborated for simultaneous processing of different sets of vapour–liquid equilibrium data. The program was tested with six binary hexane + isomeric pentanol systems, each of them measured at three different isobaric conditions and one isothermal system of tert-butyl-methyl-ether + 2-methyl-2-propanol measured at three different temperatures. The correlation uses the maximum likelihood method, taking into account real behaviour of vapour phase. The parameters obtained are valid within the whole temperature range of the data, and are consistent in comparison with those obtained from individual correlations of isobars or isotherms. Results are presented for the Wilson and NRTL equations. 相似文献
117.
Stephen G. Davies Ian A. Hunter Rebecca L. Nicholson Paul.M. Roberts Edward D. Savory Andrew D. Smith 《Tetrahedron》2004,60(35):7553-7577
α-Dibenzylamino- and α-benzyloxy- derivatives of N-acetyl-(S)-4-benzyl-5,5-dimethyloxazolidin-2-one readily undergo highly stereoselective boron mediated syn-aldol reactions with a range of aromatic and aliphatic aldehydes, generating the syn-aldol products in good to excellent yields as single diastereoisomers after purification. In the α-dibenzylamino series, deprotection of the functionalised aldol fragments to the corresponding α-amino-β-hydroxy methyl ester or α-amino-β-hydroxyaldehyde proved problematic, with a range of N- and O-protecting groups giving mixtures of products arising from endocyclic and exocyclic cleavage pathways. However, in the α-benzyloxy series, O-silyl protection of the aldol products, and subsequent DIBAL reduction gives stereoselectively the corresponding N-1′-hydroxyalkyloxazolidin-2-ones, which undergo base promoted fragmentation to the desired highly functionalised and differentially protected α,β-dihydroxyaldehydes in good yields and without loss of stereochemical integrity. 相似文献
118.
Aarnts MP Wilms MP Peelen K Fraanje J Goubitz K Hartl F Stufkens DJ Baerends EJ Vlcek A 《Inorganic chemistry》1996,35(19):5468-5477
Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) was synthesized and characterized by UV-vis, IR, (1)H NMR, (13)C NMR, (119)Sn NMR, and mass (FAB(+)) spectroscopies and by single-crystal X-ray diffraction, which proved the presence of a nearly linear Sn-Ru-Sn unit. Crystals of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB).3.5C(6)H(6) form in the triclinic space group P&onemacr; in a unit cell of dimensions a = 11.662(6) ?, b = 13.902(3) ?, c = 19.643(2) ?, alpha = 71.24(2) degrees, beta = 86.91(4) degrees, gamma = 77.89(3) degrees, and V = 2946(3) ?(3). One-electron reduction of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) produces the stable radical-anion [Ru(SnPh(3))(2)(CO)(2)(iPr-DAB)](*-) that was characterized by IR, and UV-vis spectroelectrochemistry. Its EPR spectrum shows a signal at g = 1.9960 with well resolved Sn, Ru, and iPr-DAB (H, N) hyperfine couplings. DFT-MO calculations on the model compound Ru(SnH(3))(2)(CO)(2)(H-DAB) reveal that the HOMO is mainly of sigma(Sn-Ru-Sn) character mixed strongly with the lowest pi orbital of the H-DAB ligand. The LUMO (SOMO in the reduced complex) should be viewed as predominantly pi(H-DAB) with an admixture of the sigma(Sn-Ru-Sn) orbital. Accordingly, the lowest-energy absorption band of the neutral species will mainly belong to the sigma(Sn-Ru-Sn)-->pi(iPr-DAB) charge transfer transition. The intrinsic strength of the Ru-Sn bond and the delocalized character of the three-center four-electron Sn-Ru-Sn sigma-bond account for the inherent stability of the radical anion. 相似文献
119.
Zhang X Sieval AB Hummelen JC Hessen B 《Chemical communications (Cambridge, England)》2005,(12):1616-1618
Polyethene with fullerene moieties pendant on short-chain branches was prepared by the catalytic copolymerization of ethene and a fullerene-containing vinylic comonomer, yielding polyethene copolymers containing up to 25 wt% of C60. 相似文献
120.