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121.
A polynuclear complex [Cd(endc)(H2O)]n·nH2O (endc = endo-norbomene-cis5,6-dicarboxylate anion) has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbomene-cis-5,6-dicarboxylic acid in 1:1 molar ratio,and structurally characterized by single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P21/c with a = 1.16471(7),b = 0.95334(7),c = 0.91109(9) nm,Z = 4,V= 1.01035(14)nm3,Dc.= 2.160 g/cm3,μ= 2.172 mm-1,F(000) = 648,R =0.0302 and wR = 0.0752.According to structural analysis,each Cd(Ⅱ) ion is coordinated to six O atoms from three endc anions and one water molecule,giving a distorted octahedral geometry.Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc.It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions. 相似文献
122.
A novel copper molybdate with mixed ligands, [{(Cu·phen)2(tp)}{(Cu·phen·H2O)2(tp)}{Mo4O14}] (phen=1,10-phenanthroline, tp=terephthalate) 1, has been hydrothermally synthesized and structurally characterized. The crystal belongs to monoclinic system, space group P21/c with a=13.1711(7), b=19.6132(10), c=13.6910(7) (A), β=117.6870(10)°, V=3131.8(3)(A)3, Z=2, C64H44Cu4Mo4N8O24, Mr=1946.99, Dc=2.065 g/cm3, F(000)=1920, μ(MoKα) (A) 2.198 mm-1, R=0.0810 and wR=0.2012 for 4233 observed reflections (Ⅰ > 2σ(Ⅰ)). The structural analysis indicates that the title compound contains a discrete tetramolybdate cluster decorated with copper complex fragments and tp ligands bridging the clusters into a wave-like layer. The hydrogen bonding between adjacent layers further extends the compound into a 3-D framework. 相似文献
123.
A novel coordination polymer [{Cd(hmbdc)(H2O)3}·2H2O]n (hmbdc=5-hydroxy- isophthalic acid) has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a=9.599(3), b=18.699(5), c=7.557(2) (A), β= 108.198(4)°, V=1288.6(6) (A)3, Z=4, Mr=382.60, Dc=1.972 g/cm3, F(000)=760, μ=1.740, the final R=0.0555 and wR=0.0995 for 1732 observed reflections with Ⅰ > 2σ(Ⅰ). The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework. 相似文献
124.
Ranjana Yadav 《European Polymer Journal》2007,43(8):3531-3537
Models capable of predicting the maximum extent of conversion (p) of cardanol-based novolac-type phenolic resin, have been developed using response surface methodology to determine the optimum reaction conditions. Three-dimensional response surface and their contour plot were drawn. The maximum extent of conversion (98.93%) was predicted when the cardanol was condensed with formaldehyde (molar ratio 1:0.652) at 119.84 °C for a time period of 3 h with the catalyst (e.g., citric acid) concentration of 1.988% of total volume of cardanol and formaldehyde. The pH of the reaction mixture was maintained at 3.0. These predicted values for optimum process conditions were in good agreement with experimental data. 相似文献
125.
G. Buchbauer H. Spreitzer B. Öckher C. Pretterklieber I. Piringer P. Wolschann 《Monatshefte für Chemie / Chemical Monthly》1995,126(4):467-472
Summary Guided by molecular modeling studies, the synthesis of the title compound is described. The organoleptic evaluation proved the predicted real sandal like odour of (Z)-dehydro-homo--santalol.
Aus den Diplomarbeiten von C.P. (1991), I.P. und B.Ö. (1992), Universität Wien 相似文献
126.
127.
新鄂西香茶菜素为首次从抗癌中草药鄂西香茶菜[Rabdosia henryi (Hemsl) Hara]的叶子中分离得到的二萜化合物。前人曾从毛叶香茶菜[R. japonica (Burm. f)Hara]中分离出该化合物并依据光谱数据推测其结构(右图)。但其结晶学研究尚未见报道。为研究其立体结构及分子在晶体中的排布方式,我们对该化合物的晶体进行了X射线结构分析。 相似文献
128.
This paper reports the results of a variety of experiments carried out for understanding the solvation behavior of potassium thiocyanate in methanol–water mixtures. Electrical conductivity, speed of sound, viscosity, and FT-Raman spectra of potassium thiocyanate solutions in 5 and 10% methanol–water (w/w) mixtures were measured as functions of concentration and temperature. The conductivity and structural relaxation time suggest the ion–solvent and solvent-separated ion–ion associations increase as the salt concentration increases in the mixtures. The Raman band shifts due to the C–O stretching mode of methanol for the solvent mixtures reveal the formation of methanol–water complexes. The significant changes in the Raman bands for the C–N, C–S and O–H stretching modes indicate the presence of SCN−−solvent interactions through the N-end, “free” SCN− and the solvent-shared ion pairs as potassium thiocyanate is added to the methanol–water mixtures. The relative changes corresponding to H–O–H bending and C–O stretching frequencies indicate that K+ is preferentially solvated by water in these solvent mixtures. The appearance and increase of the intensity of a broad band at ≈940 cm−1 upon salt addition was attributed to the SCN−–H2O–K+ solvent-shared ion pairs. No Raman spectral evidence for K+(H2O)n species was observed. The preferential solvation of K+ and SCN− in the methanol−water mixtures was verified by the application of the Kirkwood−Buff theory of solutions. This theory confirms that K+ is strongly preferentially solvated by water, whereas SCN− is preferentially solvated by the methanol component. 相似文献
129.
A novel type of heterogenized CuCl2 catalysts was designed for the oxidative carbonylation of methanol to dimethyl carbonate (DMC) taking account of the plausible reaction mechanism and intermediates. To prevent severe corrosion of the reaction equipment materials due to Cl– while keeping the catalytic activity of the homogeneous CuCl2 catalyst, we adopted, as supports (or ligands) of CuCl2, four polymers, bearing a 2,2-bipyridine (bpy) or pyridine (py) unit, namely, poly(2,2-bipyridine-5,5-diyl) (Pbpy), poly(pyridine-2,5-diyl) (Ppy), poly(N,N-bisphenylene-2,2-bipyridine-4,4-dicarboxylic amide) (Bpya), and poly(4-methyl-4-vinyl-2,2-bipyridine) (Pvbpy), together with one chelate compound, 8-quinolinol. The catalytic activity, stability of heterogenized CuCl2 and their corrosivities to stainless steels were examined in the liquid-phase reaction of the oxidative carbonylation of methanol. These polymer-supported catalysts showed considerable catalytic activity and stability for the DMC synthesis. In particular, the Pbpy-CuCl2 and Ppy-CuCl2 catalysts exhibited high DMC yields and selectivity comparable to those of the homogeneous CuCl2 catalyst. This high activity appears to be associated with the presence of the -conjugated system in the polymers, which affect the redox reactions of Cu involved in the catalytic reaction. All of the polymer-supported CuCl2 catalysts could be easily recycled after filtration, and the initial catalytic activity was maintained after three times of use. The corrosive characters of the catalysts were closely related to CuCl2 leaching from the supports, which reflects the ability of supports to coordinate Cu. These experimental results suggest that both the electronic structure and the coordination ability of the polymer supports are key factors for the development of an effective catalytic system. 相似文献
130.
The use of the reverse atom transfer radical polymerization (RATRP) to end-functionalize poly(methyl methacrylate) (PMMA) with fullerenes, e.g. C60 and C70 was described in this paper. The Cl-terrninated PMMA was prepared via RATRP with designed molecular weight and narrow molecular weight distributions, and then directly used to react with fullerenes to produce C60(C70) terminated PMMA polymers in the presence of CuBr/Cu/bipy or FeCl2/bipy catalysts. The resultant polymers exhibit good solubility in some common organic solvents, e.g. THF, CHCl3 and toluene, and were well structurally characterized by a variety of physical techniques. 相似文献