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21.
Abdeloihid Mellouki Robert Georges Michel Herman Deanne L. Snavely Svetlana Leytner 《Chemical physics》1997,220(3):443-322
We have recorded the infrared absorption spectrum of pyrrole at 0.005 cm−1 spectral resolution using a Fourier transform interferometer. The rotational analysis of the fundamental N---H stretch (110) at 3530.811343(82) cm−1 was performed. A set of 13 upper state rovibrational parameters was determined, allowing the 2715 assigned rovibrational lines to be reproduced with a standard deviation of 1.3 10−3 cm−1. An attempt to record the fundamental band under slit-jet conditions is reported. The role of hot bands accompanying the series of the N---H stretch excitation is investigated. Effective vibrational parameters — ω01, X011, Y111, X1,24 — are obtained. The lower level in the hot band series is unambiguously identified as the V24 = 1 level, by retrieving X1,24 independently, from other spectral data. The observation of the complex band pattern accompanying the N---H series in the higher overtone range is discussed with the help of new data, recorded around the 150 band at different temperatures using intracavity laser optoacoustic spectroscopy. 相似文献
22.
Victoria V. Lipson Irina V. Ignatenko Sergey M. Desenko Svetlana V. Shishkina Oleg V. Shishkin Sergey A. Komykhov Natalya V. Logvinenko Valery D. Orlov Herbert Meier 《Journal of heterocyclic chemistry》2003,40(6):1081-1086
The reaction of 5,7‐diphenyl‐4,7‐dihydro‐1,2,4‐triazolo[1,5‐a]pyrimidine ( 1 ) with α,β‐unsaturated carbonyl compounds 2a‐f led to the formation of the alkylated heterocycles 3a‐f (Figure 1). However, the reaction of 5‐methyl‐7‐phenyl‐4,7‐dihydro‐1,2,4‐triazolo[1,5‐a]pyrimidine ( 5 ) with 2a‐c yielded under the same conditions the triazolo[5,1‐b]quinazolines 6a‐c (Figure 3). In this case, the alkylation is followed by a cyclocondensation. The structure elucidation of the products is based on ir, ms, 1H and 13C nmr measurements and on an X‐ray diffraction study. 相似文献
23.
Thick (≈0.2–1 μm) layers of octaorganylsilsesquioxanes [RSiO1.5]8, where R is CH3, C2H3, and C2H5, were obtained by vacuum deposition and studied by X-ray diffractometry (DRON-3M, R=192 mm, CuKα radiation). Irrespective of the type of support, the layers are ideally oriented polycrystalline films with the [001] texture
axis. Structural arrangement of the layers is analyzed on the basis of the crystal data. Orientation of the terminal atomic
groups on the surface of the layer is established. It is shown that it is possible to adjust the scale of the layer pattern.
Two-layer compositions— Cu(II) β-diketonates and phthalocyanines on octaorganylsilsesquioxane supports and vice versa — with
preserved orientations of the films were obtained.
Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 923–928, September–October, 1996.
Translated by L. Smolina 相似文献
24.
Nishimura K Suzuki T Momchilova S Miyashita K Katsura E Itabashi Y 《Journal of chromatographic science》2005,43(9):494-499
A simple and highly sensitive method for determining the fatty acid composition of food lipids containing conjugated linoleic acid (CLA) is described. The method is based on the separation of the 9-anthrylmethyl ester derivatives of saturated and unsaturated (conjugated and non-conjugated) fatty acids by reversed-phase high-performance liquid chromatography with fluorescence detection. Just like the other fatty acids, CLA reacts readily with 9-anthryldiazomethane at room temperature to produce 9-anthrylmethyl esters without isomerization and decomposition of the conjugated double bonds. Clear resolution of the individual fatty acids as their 9-anthrylmethyl esters is achieved on a highly efficient octadecylsilylated silica column (150- x 3-mm i.d., 3-microm particle size) using a stepwise gradient elution with methanol-water. The method is standardized with commercially available CLA isomers (cis-9, trans-11 and trans-10, cis-12-octadecadienoic acids, and their cis,cis and trans,trans isomers) and applied for determination of the fatty acid compositions of milk and sdairy products. 相似文献
25.
Bokach NA Kuznetsova TV Simanova SA Haukka M Pombeiro AJ Kukushkin VY 《Inorganic chemistry》2005,44(14):5152-5160
Treatment of trans-[PtCl4(RCN)2] (R = Me, Et, Ph, NEt2) with 2 equiv of the amidine PhC(=NH)NHPh in a suspension of MeCN (R = Me), CHCl3 (R = Et, Ph), or in CHCl3 solution (R = NEt2) results in the formation of the imidoylamidine complexes trans-[PtCl4{NH=C(R)N=C(Ph)NHPh}2] (1-4) isolated in good yields (66-84%). The reaction of soluble complexes 3 and 4 with 2 equiv of Ph3P=CHCO2Me in CH2Cl2 (40 degrees C, 5 h) leads to dehydrochlorination resulting in a chelate ring closure to furnish the platinum(IV) chelates [PtCl2{NH=C(R)NC(Ph)=NPh}2] (R = Ph, 5; R = NEt2, 6), accordingly, and the phosphonium salt [Ph3PCH2CO2Me]Cl. Treatment of 5 with 3 equiv of Ph3P=CHCO2Me at 50 degrees C for 5 d resulted in only a 30% conversion to the corresponding Pt(II) complex [Pt{NH=C(NEt2)NC(Ph)=NPh}2] (15). The reduction can be achieved within several minutes, when Ph2PCH2CH2PPh2 in CDCl3 is used. When the platinum(II) complex trans-[PtCl2(RCN)2] is reacted with 2 equiv of the amidine, the imidoylamidinato complexes [PtCl(RCN){NH=C(R)NC(Ph)=NHPh}] (8-11) and [PhC(=NH)NHPh] x HCl (7) are formed. The reaction of trans-[PtCl2(RCN)2] with 4 equiv of the amidine under a prolonged reaction time or treatment of [PtCl(RCN){NH=C(R)NC(Ph)=NHPh}] (8-11) with 2 more equiv of the amidine yields the complex bearing two chelate rings [Pt{NH=C(R)NC(Ph)=NHPh}2] (12-15). The treatment of cis-[PtCl2(RCN)2] (R = Me, Et) with the amidine gives ca. 50-60% yield of [PtCl2{NH=C(R)NHC(Ph)=NHPh}] (16 and 17). All of the platinum compounds were characterized by elemental analyses; FAB mass spectrometry; IR spectroscopy; 1H, 13C{1H}, and 195Pt NMR spectroscopies, and four of them (4, 6, 8, and 15) were also characterized by X-ray crystallography. The coupling of the Pt-bound nitriles and the amidine is metal-mediated insofar as RCN and PhC(=NH)NHPh do not react in the absence of the metal centers in conditions more drastic than those of the observed reactions. The nitrile-amidine coupling reported in this work constitutes a route to the synthesis of imidoylamidine complexes, some of them exhibiting luminescent properties. 相似文献
26.
Sergey?P.?BabailovEmail author Dmitry?A.?Mainichev Lubov?D.?Nikulina Svetlana?S.?Petrova 《Journal of inclusion phenomena and macrocyclic chemistry》2005,51(1-2):73-78
Earlier the intramolecular inversion of the 18-crown-6 molecules was found in the complex ion pairs [Ln(ptfa)2 (18-crown-6)]+ [Ln(ptfa)4]− (H2O)4 where Ln = La(1), Ce (2), Pr (3), Nd (4), and ptfa is 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione. In this work the peculiarities of the molecular structure and dynamics were studied for [Eu(ptfa)2 (18-crown-6)]+ [Eu(ptfa)4]− (H2O)4 (5) by NMR spectroscopy techniques. Through VT-NMR spectra analysis the temperature dependence was obtained for the rate constant. The free energy ΔG‡(320) of 18-crown-6 ring inversion activation was found to be 65 ± 5 kJ mol−1 for 5 in CDCl3. This result is comparable with the earlier data [S.P. Babailov and D.A. Mainichev: J. Inclusion Phenom. Macrocyclic Chem. 43, 187–193 (2002)] for complexes 2, 3, 4 in deuterated toluene (ΔG‡(320)=65 ± 9, 64 ± 9, 64 ± 9 kJ mol−1 respectively). It was found by relaxation NMR spectroscopy that the effective distance between Ln and protons of the crown molecule is 4.5 ± 0.2 Å. The analysis of structural parameters testifies that the crown ether and chelated anions are in the first coordination sphere of a Ln cation. Obtained geometrical parameters show that the complex cations of Eu, Ce and Pr have similar spatial structures.This revised version was published online in July 2005 with a corrected issue number. 相似文献
27.
Oleg V. Mikhailov Marina A. Kazymova Tatyana A. Shumilova Galina A. Chmutova Svetlana E. Solovieva 《Transition Metal Chemistry》2005,30(1):18-21
The complexing processes in the M
II
-dithiomalonamide-diacetyl triple system (M=Ni, Cu) occuring in the nickel(II)- and copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing dithiomalonamide and diacetyl at room temperature, and between MCl2, dithiomalonamide
and
diacetyl
in
EtOH
solutions
upon
heating
to$80°C, have been studied. In the Ni
II
-dithiomalonamide-diacetyl system, template synthesis occurs in EtOH solution but does not occur in the gelatin-immobilized matrix, whereas in the Cu
II
-dithiomalonamide-diacetyl system, template synthesis occurs in the gelatin-immobilized matrix but not in EtOH solution. Dithiomalonamide and diacetyl are the ligand synthons in the processes indicated. 相似文献
28.
Svetlana Kneevi R. Milai Marjan Veber 《Fresenius' Journal of Analytical Chemistry》1998,362(1):162-166
A procedure was developed for the preconcentration and determination of aluminium and copper in dialysis concentrates at
the ng cm–3 level. The preconcentration was achieved on microcolumns filled with Chelex-100 resin adjusted to a pH of 4.0. Five repetitive
cycles of the sample through the column ensured a sufficient contact time for quantitative retention of aluminium and copper
ions. The retained ions were eluted with HNO3 (0.5 mol dm–3). Aluminium and copper were determined in the eluate by Zeeman ETAAS using the standard addition technique. The procedure
was performed under clean room conditions (class 10,000), The reliability of the results was evaluated by recovery tests,
using dialysis concentrates spiked with aluminium and copper. The recoveries obtained ranged from 86 to 106% for aluminium
and from 92 to 97% for copper. Using the recommended procedure, the LOD of aluminium and copper in dialysis concentrates (preconcentration
factor 2) was found to be 0.5 ng cm–3 and 0.2 ng cm–3, respectively.
Received: 19 December 1997 / Revised: 10 March 1998 / Accepted: 28 March 1998 相似文献
29.
Sokolov MN Gushchin AL Virovets AV Peresypkina EV Kozlova SG Fedin VP 《Inorganic chemistry》2004,43(25):7966-7968
Black single crystals of Ta(4)Se(9)I(8) are obtained in a high yield by heating Ta, Se, and I(2) at 300 degrees C in 1:2.2:1.0 molar ratio. In the structure, the tantalum atoms form a square, with four Se(2) ligands bridging the Ta-Ta edges and one capping the square. Each Ta atom has two terminal iodine atoms. The compound is diamagnetic and has only two electrons for metal-metal bonding. 相似文献
30.
Mitrovski SM Elliott LC Nuzzo RG 《Langmuir : the ACS journal of surfaces and colloids》2004,20(17):6974-6976
We describe the fabrication and performance of a passive, microfluidics-based H2-O2 microfluidic fuel cell using thin film Pt electrodes embedded in a poly(dimethylsiloxane) (PDMS) device. The electrode array is fully immersed in a liquid electrolyte confined inside the microchannel network, which serves also as a thin gas-permeable membrane through which the reactants are fed to the electrodes. The cell operates at room temperature with a maximum power density of around 700 microW/cm(2), while its performance, as recorded by monitoring the corresponding polarization curves and the power density plots, is affected by the pH of the electrolyte, its concentration, the surface area of the Pt electrodes, and the thickness of the PDMS membrane. The best results were obtained in basic solutions using electrochemically roughened Pt electrodes, the roughness factor, R(f), of which was around 90 relative to a smooth Pt film. In addition, the operating lifetime of the fuel cell was found to be longer for the one using higher surface area electrodes. 相似文献