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261.
Chun‐Xiang Wang Zhi‐Feng Li Ping Wang 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):m473-m475
In the title compound, [Nd2(C4H4O4)2(C2O4)(H2O)2]n, the flexible succinate anion assumes the gauche conformation and bridges the nine‐coordinate Nd atoms to generate two‐dimensional layers parallel to (010). The coordination polymer layers are linked into a three‐dimensional framework by the rigid oxalate ligands. The oxalate ions are located on a center of inversion. 相似文献
262.
Ming‐Zhong Wang Yan‐Yan Zhang Shun‐Lin Li Xiang‐Hai Cai Xiao‐Dong Luo 《Helvetica chimica acta》2006,89(12):3104-3108
A new norsesquiterpene named eupatorone (= (4S,4aR,6R)‐1‐acetyl‐6‐(acetyloxy)‐4,4a,5,6‐tetrahydro‐4,7‐dimethylnaphthalen‐2(3H)‐one; 1 ) and a new sesquiterpene derivative named 2‐deoxo‐2‐(acetyloxy)‐9‐oxoageraphorone (= (1R,4S,4aR,6R,8aS)‐6‐(acetyloxy)‐3,4,4a,5,6,8a‐hexahydro‐4,7‐dimethyl‐1‐(1‐methylethyl)naphthalen‐2(1H)‐one; 2 ), together with the five known cadinene derivatives 3 – 7 were isolated from the flower of Eupatorium adenophorum (Spreng. ). Their structures were established by extensive NMR experiments, including 1D and 2D NMR. 相似文献
263.
Chun‐Xiang Wang Chen‐Xia Du Zhi‐Feng Li 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(10):m488-m490
In the title compound, [Zn(C17H10N5O)2(H2O)2]·4H2O, cyclic water hexamers forming one‐dimensional metal–water chains are observed. The water clusters are trapped by the co‐operative association of coordination interactions and hydrogen bonds. The ZnII ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two O atoms and two N atoms from two 2′‐(4,5‐diazafluoren‐9‐ylidene)picolinohydrazidate ligands and two water molecules. 相似文献
264.
Cu(I)/Diamine-catalyzed Aryl-alkyne Coupling Reactions 总被引:1,自引:0,他引:1
Ye Feng WANG Wei DENG Lei LIU Qing Xiang GUO 《中国化学快报》2005,16(9):1197-1200
Arylalkynes are important building blocks for the synthesis of natural products,pharmaceuticals,and artificial molecular devices1.They are often synthesized via the Pd-catalyzed Sonogashira coupling reactions between aryl halides and terminal alkynes2,3.Unfortunately,it remains difficult to apply the Sonogashira reaction to industrial scale and/or pharmaceutical synthesis,due to the high cost of Pd and the difficulty in removing the toxic Pd residues from the reaction products.Thus it is wor… 相似文献
265.
The covalent binding of pyrazine on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS) and x-ray photoelectron spectroscopy. Experimental results clearly suggest that the attachment occurs exclusively through the bonding of the two para-nitrogen atoms with the surface without the involvement of the carbon atoms, as evidenced from the retention of the (sp2) C-H stretching mode in HREELS and a significant down shift of 1.6 eV in the binding energy of N 1s. The binding mechanism for pyrazine on Si(100) demonstrates that reaction channels for heteroatomic aromatic molecules are strongly dependent on the electronic properties of the constituent atoms. 相似文献
266.
Xiang‐Gao Meng Chun‐Shan Zhou Li Wang Chang‐Lin Liu 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):o667-o670
5‐Sulfosalicylic acid (5‐SSA) and 3‐aminopyridine (3‐APy) crystallize in the same solvent system, resulting in two kinds of 1:1 proton‐transfer organic adduct, namely 3‐aminopyridinium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate, C5H7N2+·C7H5O6S−·H2O or 3‐APy·5‐SSA·H2O, (I), and the anhydrous adduct, C5H7N2+·C7H5O6S− or 3‐APy·5‐SSA, (II). Both compounds have extensively hydrogen‐bonded three‐dimensional layered polymer structures, with interlayer homo‐ and heterogeneous π–π interactions in (I) and (II), respectively. 相似文献
267.
Rh- or Ru-catalyzed highly enantioselective hydrogenation of N-phthaloyl enamides is presented. Electron-rich TangPhos and DuanPhos are found to be effective ligands for Rh-catalyzed hydrogenation of α-aryl enamides and up to 99% ee has been achieved. In contrast, for the hydrogenation of α-alkyl enamide, the Ru-C3-TunePhos complex is more effective and up to 69% ee can be observed. This work is the first report of the hydrogenation of N-phthaloyl enamides. 相似文献
268.
Lijun X Bochu W Zhimin L Chuanren D Qinghong W Liu L 《Colloids and surfaces. B, Biointerfaces》2005,40(1):25-29
We studied the LAS degradation of immobilized Pseudomonas aeruginosa with low-intensity ultrasonic and the influence of original LAS concentration, pH, rotary velocity and different conditions of low-intensity ultrasonic irradiation on the degradation of LAS. In our experiment, the degradation rate of LAS was the main index. We found that low-intensity ultrasonic irradiation could improve the metabolism of microorganism cells and promote the LAS biodegradation of immobilized cells. In the experiment, 50 mg/l LAS were used to simulate wastewater, and low-intensity ultrasonic was considered. We found the influence was obvious, and the optimal degradation rate was acquired when the conditions of ultrasonic were frequency 24 kHz, power 8 W, stimulation time 5 s, intermissive time 30 s, and total time 10 min. The LAS degradation rate of immobilized cells with ultrasonic were respectively 40% and 9.5% higher than that of the suspending cells and immobilized cells without irradiation. 相似文献
269.
用TRP技术研究了以全硅MCM-41(Si-MCM-41)和HNO3交换的全硅MCM-41(H-MCM-41)为载体制备的Ni-Mo、Co-Mo和Ni-W加氢脱硫(HDS)催化剂的还原性能,并以0.8(wt)%二苯并噻吩(DBT)的十氢萘溶液为模型化合物,在高压固定床反应器上考察了上述催化剂的加氢脱硫(HDS)反应性能。结果表明,Si-MCM-41经稀HNO3交换后,所担载的Ni-Mo和Ni-W催化剂还原性能、HDS活性和加氢活性有显著变化,但对Co-Mo催化剂影响不大。这说明在Ni-Mo/H-MCM-41和Ni-W/H-MCM-41中可能存在氢溢流现象,DBT的HDS活性与载体表面酸性和氢溢流有关。 相似文献
270.
The first thermodynamic dissociation constants of o-phthalic acid were determined at five temperatures from 278.15 to 318.15 K in 10, 14.93 and 20 wt% isopropanol-water solvent mixtures, by precise e. m. f. measurements of hydrogen-silver chlorld electrodes in cells without liquid junction. On the basis of Pitzer's theory, the method of polynomial approximation was used to determine the dissociation constants of H_2P and the results obtained were compared with traditional extrapolation according to the extended Debye-Huckel equation Results obtained from both methods agree within experimental error. The dependence of the first thermodynamic dissociation constant on temperature was given as a function of the thermodynamic temperature T by the empirical equation: pK_1=A_0+A_1/T+A_2/T. The thermodynamic quantities of dissociation in the mixed solvents have been calculated, and the results have been discussed. 相似文献