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991.
Three novel Schiff base cadmium(II) complexes, derived from the end‐on (μ‐1,1‐N3) azide or end‐to‐end (μ‐1,3‐NCS) thio cyanate bridges and similar tridentate Schiff base ligands, have been synthesized under similar synthetic procedures and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Cd2(L1)2(N3)2(μ‐1,1‐N3)2] ( 1 ), the dinuclear double end‐on azide‐bridged [Cd2(L2)2(N3)2(μ‐1,1‐N3)2] ( 2 ), and the dinuclear double end‐to‐end thiocyanate‐bridged [Cd2(L3)2(NCS)2(μ1,3‐NCS)2] ( 3 ), where L1, L2 and L3 are three similar tridentate Schiff bases obtained by condensation of 2‐pyridylaldehyde with N,N‐diethylethane‐1,2‐diamine, of 2‐pyridylaldehyde with N‐isopropylethane‐1,2‐diamine, and of 2‐pyridylaldehyde with N,N‐dimethylpropane‐1,3‐diamine, respectively. Each cadmium(II) centre in the complexes is in a distorted octahedral coordination. There is a crystallographic inversion centre in each of the complexes. The similar small ligands used as the secondary ligands in the preparation of the cadmium(II) complexes with similar Schiff bases can result in similar structures. 相似文献
992.
Zhao L Zhu G Zhang D Di Y Chen Y Terasaki O Qiu S 《The journal of physical chemistry. B》2005,109(2):764-768
Using 1,2-bis(trimethoxysilyl)ethane as organosiloxane precursor and a triblock copolymer surfactant, Pluronic F127, as template, a highly ordered mesoporous organosilica with large cagelike pores has been successfully synthesized. Its structure was resolved to be 3-D cubic Fmm by high-resolution transmission electron microscopy. The intergrowth of hexagonal close-packed and cubic close-packed phases was observed in this material. The effect of different siliceous precursors on the mesostructure was also investigated. 相似文献
993.
Aliphatic and aromatic 1,3‐dithiane are oxidized to the corresponding carbonyl compounds in good yields under mild conditions by N,N′‐diiodo‐N,N′‐1,2‐ethanediyl‐bis(p‐toluenesulphonamide) [NIBTS] and silver nitrate. 相似文献
994.
A rapid flow-injection method with chemiluminescence (CL) detection is described for the determination of glutathione (GSH).
The method is based on the CL reaction of luminol and hydrogen peroxide. GSH can greatly enhance the chemiluminescence intensity
in 0.1 mol/L borax–sodium hydroxide buffer solution (pH = 9.7). The maximum CL intensity was directly proportional to the
concentration of GSH in the range 3.0 × 10−7–2.0 × 10−5 mol/L, and the detection limit was 6.8 × 10−8 mol/L. The relative standard deviation was 3.4% for 5.0 × 10−6 mol/L of GSH (n = 11).
Received October 23, 2001; accepted June 18, 2002 相似文献
995.
The new unsymmetrical N‐bridgehead, apo (zeromethine), mono‐methine, dimethine, meso substituted tetramethine and styryl cyanine dyes incorporating pyrazolo (4,5‐b) indolizine (benzoindolizine) nuclei were prepared. Structural confirmation was carried out by elemental analyses, IR, H‐NMR, mass spectra and 13C‐NMR with the aid of carbon DEPT spectral data. The visible absorption spectra for the newly synthesized cyanines were examined in 95% ethanol. 相似文献
996.
Yu‐Hsiang Hu Chuh‐Yung Chen 《Journal of polymer science. Part A, Polymer chemistry》2002,40(21):3692-3702
The bulk polymerization of methyl methacrylate initiated with 2‐pyrrolidinone and n‐dodecyl mercaptan (R‐SH) has been explored. This polymerization system showed “living” characteristics; for example, the molecular weight of the resulting polymers increased with reaction time by gel permeation chromatographic analysis. Also, the polymer was characterized by Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR techniques. The polymer end with the iniferter structures was found. By the initial‐rate method, the polymerization rate depended on [2‐pyrrolidinone]1.0 and [R‐SH]0. Combining the structure analysis and the polymerization‐rate expression, a possible mechanism was proposed. n‐Dodecyl mercaptan served dual roles—as a catalyst at low conversion and as a chain‐transfer agent at high conversion. Finally, the thermal properties were studied, and the glass‐transition temperature and thermal‐degradation temperature were, respectively, 25 and 80–100 °C higher than that of the azobisisobutyronitrile system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3692–3702, 2002 相似文献
997.
Qiutian Liu Chunxi Zhang Changneng Chen Hongping Zhu Yuheng Deng Jinhua Cai 《中国科学B辑(英文版)》1997,40(6):616-623
In a reaction system consisting of FeCl2, tetrathiometallate and cycloalkylthiolate, two Fe4S4 cubanelike cluster compounds were obtained with the following crystallographic data: (PhCH2NMe3)2 [ Fe4S4 (SC5H9)4] (I), monoclinic space groupP21/c,a = 1.632 7(4),b=1.122 9(3),c = 2. 802 5(10) nm, β= 94.63(2)°, Z=4, andR= 0.074; (Et4N)2[F4S4(SC6HlI)4] (II), tetragod space group
,a = l.167 05(9),b = 1.167 06(2),c = 2.063 26(5) nm,Z = 2, Dobs = 1. 28 g/cm3, andR = 0. 078. The participation of cycloalkylthiolate ligand does not obviously arouse the change of the Fe4S4 core structure. Meanwhile, the influence of the cation on the structural symmetry of the Fe4S4 cluster dianion is also discussed.
Project supported by the National Natural Science Foundation of China and the Climbing Program Foundation of China. 相似文献
998.
J. Ho L. Zhu E. K. Parks S. J. Riley 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(1):331-333
The kinetics of chemical reactions of cobalt clusters Con with deuterium are described. Absolute rate constants have been measured in the size range n=7–68 at 293 K. The rate constants are found to be a strong function of cluster size, varying by a factor of 400. This size dependence is most prominent for n=7 to 25: Co15 is the most reactive cluster, and Co7–9 and Co19–20 are particularly unreactive. Abrupt changes in the rate constants from one cluster size to the next are observed. For the clusters above n=25, the rate constants show several less prominent maxima and minima superimposed on a slow, nearly monotonic increase with cluster size. 相似文献
999.
Tonggang Jiu Yongjun Li Haiyang Gan Yuliang Li Huibiao Liu Shu Wang Weidong Zhou Chunru Wang Xiaofang Li Xiaofeng Liu Daoben Zhu 《Tetrahedron》2007,63(1):232-240
The oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) (P-OPVn, n=2, 4, where n is the number of phenyl rings) and the complex with Zn2+ based on P-OPVn were synthesized for investigating their photophysical properties via UV-vis, voltammetry, steady-state and time-resolved fluorescence spectra. In these molecules two OPV moieties as energy donors were linked to porphyrin center by virtue of Wittig reaction. The detailed studies of photophysical properties indicate that OPV group can act as an antenna unit for effective intramolecular energy transfer. 相似文献
1000.
Jorge Bravo Jesús Castro Soledad García‐Fontn Elvira M. Lamas Pilar Rodríguez‐Seoane 《无机化学与普通化学杂志》2003,629(2):297-302
The manganese carbonyl complex [MnBr(CO)3 L ] ( 1 ), where L = Ph2POCH2CH2OPPh2, was prepared by reacting [MnBr(CO)5] with the bidentate ligand 1, 2‐Bis(diphenylphosphinite)ethane. From this compound and the appropriate phosphite, phosphinite or phosphonite ligands were synthesized the complexes [MnBr(CO)2 LL ′], where L ′ = P(OMe)3 ( 2 ) or P(OEt)3 ( 3 ) and [MnBr(CO)3 L ′2], where L ′ =PPh(OEt)2 ( 4 ) or PPh2(OEt) ( 5 ). The obtained compounds have been characterized by elemental analysis, mass spectrometry, IR and NMR (1H, 13C and 31P) spectroscopies and X‐ray diffractometry for the complexes 1 , 4 and 5 . 相似文献