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891.
892.
893.
An oligosaccharide homologue named SnS-2 was isolated from the root of Scrophularia ningpoensis Hemsl.SnS-2 was purified by means of gel-permeation chromatography and ion-exchange chromatography. Its physicochemical properties, including carbohydrate content and molecular weight were determined. The structure of SnS-2 was elucidated by chemical methods along with ^1H and ^13C NMR spectroscopy, including two-dimensional DQCOSY and H-detected ^1H, ^13C HMQC experiments. These results show that SnS-2 possesses a backbone consisting of terminal α-Galp-(1→, α-Galp-(1→6), α-Glcp-(1→6) and nonreducing end β-Fruf-(2→. The bioactive assay showed that it could inhibit the growth of Lewis pulmonary carcinoma implanted in mice. 相似文献
894.
[structure: see text] A convergent, stereoselective total synthesis of the macrolide antitumor agent rhizoxin D is described. (+)-DIPCl-promoted asymmetric aldol reaction, Evans-Tishchenko 1,3-diol synthesis, modified Julia coupling, and Horner-Wadsworth-Emmons reactions are featured. 相似文献
895.
Single crystals of {[Cu(TO)2(H2O)2](NO3)2}n (TO: 1, 2, 4‐triazol‐5‐one) were grown by slow evaporation from aqueous solution. It crystallizes in the orthorhombic space group Pbca, with a = 7.082(1), b = 10.285(1), c = 17.911(3)Å, V = 1304.6(3)Å3, Z = 4. The CuII distorted octahedra are bridged by bidentate TO ligands into infinite 2‐D interlaced rhombic grid‐like network planes, {[Cu(TO)2(H2O)2]2+}n. Hydrogen bonds, electrostatic interactions, and weak van der Waals' forces assemble these planes and the NO3— anions to a layered structure. The title compound decomposes at 153.4 °C to the final products, Cu(CN)2 and CuO. 相似文献
896.
Jian Zhang Zhao‐Ji Li Yi‐Hang Wen Yao Kang Jian‐Kai Cheng Yuan‐Gen Yao 《无机化学与普通化学杂志》2004,630(15):2731-2735
Two new metal succinates modified by rigid bipyridines, Cd(4, 4′‐bpy)(C4H4O4)·1/4H2O ( 1 ) and Cu(2, 2′‐bpy)(C4H4O4)0.5(NO3)(H2O) ( 2 ) (bpy = bipyridine), have been synthesized by hydrothermal reactions and structurally determined. Complex 1 crystallizes in the orthorhombic space group Cmca with the cell parameters a = 11.696(2), b = 15.554(2), c = 15.874(3) Å, α = β = γ = 90.00°, V = 2888(3) Å3, Z = 8. Complex 2 crystallizes in the triclinic space group with a = 7.077(1), b = 9.838(2), c = 10.461(2) Å, α = 71.941(3)°, β = 73.078(3)°, γ = 74.502(3)°, V = 649.8(2) Å3, Z = 2. In complex 1 , a 2‐D network was formed by Cd‐succinato bonding. The 2‐D networks are pillared by 4, 4′‐bpy ligands, forming a 3‐D grid framework. The 2‐fold interpenetration of the resulting 3‐D frameworks completes the molecular structure. In complex 2 , the CuII atom adopts a distorted octahedral in which the CuII atoms are bridged by two H2O molecules into an infinite zigzag chain, [Cu2(H2O)2(C4H4O4)]n. The neighboring chains are further linked by π‐π stacking interactions into a 2‐D network, and the interlayer hydrogen bonds lead to the final 3‐D crystal structure. 相似文献
897.
Yu‐Biao Chen Yao Kang Ye‐Yan Qin Zhao‐Ji Li Jian‐Kai Cheng Yuan‐Gen Yao 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):m263-m265
The title compound, [Ag2(NO3)2(C5H5NS)]n, was obtained from the reaction of silver nitrate with bis(4‐pyridyl) disufide (4‐PDS) in a mixture of ethanol and water, which suggests that the disulfide bond of 4‐PDS can be cleaved under mild conditions. The structure of the title compound is a two‐dimensional infinite array in which the asymmetric unit contains two Ag atoms, a pyridinium‐4‐thiolate molecule and two nitrate groups. Each pyridinium‐4‐thiolate molecule acts as a μ4 bridge, linking four Ag atoms, with Ag—S bond distances of 2.4870 (19), 2.5791 (19), 2.5992 (19) and 2.848 (2) Å. The Ag⋯Ag distances lie in the range 2.889 (2)–3.049 (1) Å. 相似文献
898.
The structure of [CoCl2(C6H4N3CH2Ph)2] has been determined by X-ray crystallography. It is also characterized by elemental analysis, IR and electronic spectroscopy, and by thermogravimetric differential thermal analysis. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 16.133(3) , b = 11.355(2) , c = 15.637(3) , = 117.22(3)°, and Z = 8. The crystal structure of the title compound consists of monomeric molecules of [CoCl2(C6H4N3CH2Ph)2] with slightly distorted tetrahedron geometry for the CoCl2N2 chromophore. The thermal gravimetry (TG) data indicate that there are four decomposition steps with five endothermic peaks. The final product of the thermal decomposition is CoCl2. Elemental analysis and the electronic and IR spectra are in agreement with the structural data.Original Russian Text Copyright © 2004 by F. Jian, H. Wang, and H. XiaoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 723–728, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
899.
Cao XY Liu XH Zhou XH Zhang Y Jiang Y Cao Y Cui YX Pei J 《The Journal of organic chemistry》2004,69(18):6050-6058
This paper reports the facile synthetic strategy of a series of novel pi-conjugated dendrimers (G0 and G1) based on 10,15-dihydro-5H-diindeno[1,2-a;1',2'-c]fluorene (truxene) in which the benzene cores are generated "in-situ" from acetyl aromatics by the acid-promoted cyclotrimerizations. The unique NMR behaviors, physical properties, and electroluminescence device applications are also presented. Besides the purity, the structure, and the confirmation of the successful formation and isolation of desired compounds by clear assignments of every molecule by (1)H and (13)C and 2D NMR characterizations, several astonishing NMR behaviors have been observed in various solvents. For 1, chemical shift values belonging to H-2' of hexyl substituents move to the most upfield; however, such chemical shift values move from 0.48 to 0.85 ppm when pyridine-d(5) or benzene-d(6) is used as solvent. Our dendrimers as the emissive layers in organic light-emitting diodes gave blue-green light with an external quantum efficiency up to 0.16% both for G0 and for G1 in nitrogen, respectively, which exhibit unique electroluminescence spectra in comparison with their corresponding photoluminescence ones. 相似文献
900.
Fabrication of alternating polycation and albumin multilayer coating onto stainless steel by electrostatic layer-by-layer adsorption 总被引:1,自引:0,他引:1
Ji J Tan Q Fan DZ Sun FY Barbosa MA Shen J 《Colloids and surfaces. B, Biointerfaces》2004,34(3):185-190
Multilayer films consisting of polyethylenimine (PEI) and albumin were successfully prepared on biomedical 316L stainless steel surface via electrostatic self-assembly of the PEI and albumin. The process of electrostatic self-assembly of PEI/albumin was monitored by125I radiolabeling, electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM). The EIS data revealed that the multilayer coating was stable in Tris-HCl (pH 7.35) buffer solution for 21 days. 125I radiolabeling experiments indicated that less than 10% albumin was eluted by PBS in 45 days. Static platelet adhesion experiments indicated that the PEI/albumin deposited on stainless steel could resist platelet adhesion effectively. Such an easy processing and shape-independent method may have good potential for surface modification of cardiovascular devices. 相似文献