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91.
An explicit formula is derived for calculating the delocalization corrections (tails) to be added to the strictly localized bond orbitals. It was obtained by solving analytically the SCF problem for the interbond interactions in a linearized approximation. The model calculations at the CNDO/2 level show that this simple approach is sufficient to account for the molecular conformations. 相似文献
92.
Helmut Viernstein Petra Weiss-Greiler Peter Wolschann 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):235-240
The solubility enhancement of triflumizole by complexation with -cyclodextrin and with dimethyl--cyclodextrin is compared with respect to the different physico-chemical properties of the host molecules. Although the inclusion reaction constants are rather similar for both complexation reactions, a completely different temperature dependence of the host-guest interaction is observed, which indicates a change of the reaction mechanisms. Moreover, the influence of ethanol as cosolvent is studied. 相似文献
93.
94.
A resonance light scattering (RLS) imaging method was proposed based on imaging and measuring the RLS features of single suprahelical species of DNA, and its appfication to DNA assay was also investigated. In acidic medium, porphine-5,10,15,20-tetrakis(p-phenyltlimethylaminium) (PTPTMA), could stack along the molecular surface of DNA with the mode of long-range assembly to induce the formation of suprahelical species of DNA, resulting in strong RLS signals in the range of 450-510 nm. Under the excitation of 488 nm fight beam of argon ion laser source, single suprahelical species could be observed with the aid of a common microscope due to the strong scattered fight emitted by the suprahelical species. By capturing the RLS images of the single suprahelical species with a cooled charge coupled device (CCD) camera, and analyzing the RLS data, herein an RLS imaging method of DNA was proposed based on the linear relationship between the counts of suprahelical species in the detection focus plane and the concentration of DNA in nanograms. When 1.8 μmol/L PTPTMA was employed, both calf thymus DNA (ct DNA) and fish sperm DNA (fs DNA) in the range of 25-1100 ng/mL could be detected with the limits of detection lower than 25 ng/mL (3a). Four synthetic samples were detected satisfactorily with relative standard deviations less than 5.1%. 相似文献
95.
Andreas G. Galinos Spyros P. Perlepes Theodore F. Zafiropoulos Panayiotis V. Ioannou John K. Kouinis 《Monatshefte für Chemie / Chemical Monthly》1981,112(10):1113-1121
The preparation and some properties of the cobalt(II) complexes Co(LH2)Cl2·2H2O, Co(LH2(NCS)2 and CoL·H2O (whereLH2=N,N-(dipicolyl)-1,8-naphthylenediamine) are reported. On the basis of magnetic moments, visible reflectance and IR data, the structure is proposed to be pseudo-octahedral for Co(LH2)Cl2·2 H2O, pseudo-tetrahedral for Co(LH2)(NCS)2 and square planar for CoL·H2O.
Deprotonierte und Nicht-deprotonierte Co(II)-Komplexe des vierzähnigen Bisamid-Liganden N,N-(Dipicolyl)-1,8-naphthyldiamin. Drei verschiedene Koordinationstypen
Zusammenfassung Es werden die Darstellung und einige Eigenschaften der Kobalt(II)-Komplexe Co(LH2)Cl2·2 H2O, Co(LH2)(NCS)2 und CoL·H2O [LH2=N,N-(dipicolyl)-1,8-naphthylendiamin] diskutiert. Auf der Grundlage von magnetischen Momenten, von Daten der sichtbaren Reflektions-und IR-Spektren wird eine pseudooctaedrische Struktur für Co(LH2)Cl2·2H2O, eine pseudotetraedrische für Co(LH2)(NCS)2 und eine planar-quadratische für CoL·H2O vorgeschlagen.相似文献
96.
Masaki Tachibana Motohisa Furusawa Nobutoshi Kiba 《Journal of inclusion phenomena and macrocyclic chemistry》1995,22(4):313-329
Extraction of carbazole in heptane was performed at 25±1°C with an aqueous dimethyl sulfoxide (DMSO) medium containing -cyclodextrin (CD) at consecutive concentrations in the range of 0–10 mM. The fluorescence intensity of carbazole remaining in the heptane phase was measured by synchronous scanning fluorimetry. The apparent formation constant (K
f) for a 1:1 carbazole: CD inclusion complex in water-DMSO medium was determined by using a linear plot of the distribution ratio calculated from the fluorescence intensities vs. the -CD concentration. The values thus obtained ranged from 477 M–1 in a 10% v/v DMSO medium to 12.1 M–1 in a 60% v/v medium. Good linear relationships were observed between logK
f and the DMSO concentration ([DMSO]), and also between logK
f and the logarithm of the distribution coefficient (K
d) for carbazole. The formation constant in 100% water was estimated to be approximately 1.0×103 M–1 on the basis of the logK
f vs. [DMSO] and the logK
f vs. logK
d correlations. 相似文献
97.
J. Ch. Pomerol 《Mathematical Programming》1980,19(1):352-355
We give a new minisup theorem for noncompact strategy sets. Our result is of the type of the Matthies-Strang-Christiansen minimax theorem where the hyperplane should be replaced by any closed convex set. As an application, we derive a slight generalization of the Matthies-Strang-Christiansen minimax theorem. 相似文献
98.
L. N. Novikova B. A. Mazurchik N. A. Ustynyuk S. V. Kukharenko V. V. Strelets 《Russian Chemical Bulletin》1994,43(2):299-303
New cationic complexes [(6-C13H10)Fe(5-Cp*)]PF6 and [(6-9-CH3-C13H9)Fe(5-Cp*)]PF6 were obtained by the reaction of Cp*Fe(CO)2Br with fluorene and 9-methylfluorene, respectively. Deprotonation of these complexes byt-BuOK in THF affords zwitter-ionic compounds (6-C13H9)Fe(5-Cp*) and (6-9-CH3-C13H8)Fe(5-Cp*) (A). WhenA is heated in nonane at 150 °C it undergoes 65 inter-ring rearrangement with the formation of hexamethyldibenzoferrocene (B). The electrochemical behavior ofA andB was studied by cyclic voltammetry. One-electron reduction ofA andB to the corresponding radical anions induces inter-ring haptotropic rearrangementA
.–B
.–. The equilibrium in the 19 state is shifted to the 6-isomeric radical anionA
.–, while in the 18 precursors, it shifts to the 5-isomerB.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 319–324, February, 1994.The authors are grateful to D. V. Zagorevskii (A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences) for recording and interpreting the mass spectra, and to A. A. Borisenko (Moscow State University) for recording the NMR spectra.This work was financially supported by the Russian Foundation for Basic Research (Grant 93-03-5209). 相似文献
99.
Polyfluoroalkyl-containing aziridinyl ketones, unlike their nonfluorinated analogs, react with hydrogen halides to give only -halo- -anvnoketones or their hydrogen halide salts. Thermal decomposition of the latter in the case where Hal = CI affords -chlorovinyl ketones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 684–686, March, 1996. 相似文献
100.
S. A. Gromilov I. A. Baidina P. A. Stabnikov G. V. Romanenko 《Journal of Structural Chemistry》2004,45(3):476-481
An X-ray diffraction investigation has performed for copper(II) bis-hexafluoroacetylacetonate (Bruker AXS P4 automatic diffractometer, MoK
radiation, t = –25°C). Crystal data for C10H2CuF12O4: a = 5.530(1) Å, b = 6.038(1) Å, c = 11.266(2) Å, = 95.948(3)°, = 101.743(3)°, = 92.298(3)°, space group; P1, V = 365.6(1) Å3, Z = 1, d
calc = 2.169 g/cm3. The square-planar environment of the copper atom (Cu-Oav 1.912 Å, O-Cu-Oav 93°) is completed to bipyramidal by two fluorine atoms of the neighboring molecules, Cu...F 2.71 Å and 2.75 Å.Original Russian Text Copyright © 2004 by S. A. Gromilov, I. A. Baidina, P. A. Stabnikov, and G. V. RomanenkoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 502–507, May–June 2004. 相似文献