116 resultados para 2,3-butanedione
Resumo:
由2-(1,2-亚乙二硫)亚甲基-3-羰基-5-芳基-4-戊烯酸与三苯基氢氧化锡反应,合成了九个标题化合物3.用X射线衍射法测定了3b的晶体结构.该晶体属三斜晶系,空间群Pl,α=0.9074(2)nm,b=1.6809(3)nm,c=2.1834(4)nm,α=77.57(3)°,β=88.04(3)°,γ=89.47(3)°,V=3.2503nm~3,Z=2;R=0.0592.由锡氧原子间距离可推测,该晶体中羧酸根作为双齿配体与锡原子形成了分子内五配位结构.
Resumo:
采用激光解吸电离飞行时间质谱 (LDI TOF MS)快速测定了 1H 2 ,3 二氢 1 吡咯里嗪酮衍生物相对分子质量 ,初步总结了该类化合物的质谱规律 .实验中不需加入基质 ,实测值与理论计算值相吻合.
Resumo:
The title compound, [H3PMo12O40][CO(NH2)(2)](3). 5H(2)O, was synthesized and characterized by IR, C-13 NMR and X-ray diffraction. This is the first example of a urea-heteropoly acid species. Crystal data: monoclinic, C2/c, a = 17.790(4) Angstrom, b = 17.158(3) Angstrom, e = 25.512(5) Angstrom, beta = 100.65(3)degrees, V = 8514(3) Angstrom (3), Z = 6, R-1 = 0.0437, wR2 = 0. 1092. In the unit cell, the urea molecules occupy cavities in the polyoxometalate lattice ordered along b-axis. Water molecules occupy the space left by polyoxometalates, and urea. Polyoxometalate O atoms, the N atoms of urea and O atoms of water molecules are involved in hydrogen bonding. (C) 2001 Elsevier Science B.V. All rights reserved.
Resumo:
The characterization of free base porphyrin 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and its zinc(II) complexes [Zn(II)OHTTAP] containing eight thioether groups at the beta -pyrrole positions of the macrocycle was reported. Results obtained by cyclic voltammetry and differential pulse voltammetry indicated a five-electron reduction in five steps for each complex. They were oxidized in two single-electron-transfer steps to yield pi -cation radicals and dications and reduced in three single-electron-transfer steps to yield pi -anion radicals, dianions and trianions, respectively. The redox property of H(2)OHTTAP was unusual as compared to porphyrins (PPs) and phthalocyanines (Pcs). Each process was monitored by in situ thin-layer spectroelectrochemistry, which indicated that only the Ligand was electroactive. The existence of the eight hexylthio groups was responsible for the intrastack interactions and enhanced intracolumnar and intercolumnar electron motions, resulting in improved conductivity. Copyright (C) 2001 John Wiley & Sons, Ltd.
Resumo:
合成了 3个三环己基锡 -2 -( 1 ,2 -亚乙二硫 )亚甲基 -3-羰基 -5 -芳基 -4 -戊烯酸酯化合物 .用 IR,1 H NMR,1 3 C NMR和 1 1 9Sn NMR光谱及 X射线衍射对所合成的化合物进行了表征 .结果表明标题化合物为四配位、具有畸变四面体结构的锡酯类化合物
Resumo:
2,2,'3,3' -Biphenyltetracarboxylic dianhydride (2,2,'3,3'-BPDA) was prepared by a coupling reaction of dimethyl 3-iodophthalate. The X-ray single-crystal structure determination showed that this dianhydride had a bent and noncopolanar structure, presenting a striking contrast to its isomer, 3,3,'4,4'-BPDA. This dianhydride was reacted with aromatic diamines in a polar aprotic solvent such as N,N-dimethylacetamide (DMAc) to form polyamic acid intermediates, which imidized chemically to polyimides with inherent viscosities of 0.34-0.55 dL/g, depending on the diamine used. The polyimides from 2,2,'3,3'-BPDA exhibited a good solubility and were dissolved in polar aprotic solvents and polychlorocarbons. These polyimides have high glass transition temperatures above 283 degrees C. Thermogravimetric analyses indicated that these polyimides were fairly stable up to 500 degrees C, and the 5% weight loss temperatures were recorded in the range of 534-583 degrees C in nitrogen atmosphere and 537-561 degrees C in air atmosphere. All polyimides were amorphous according to X-ray determination. (C) 1999 John Wiley & Sons, Inc.
Resumo:
用一维 1HNMR、13CNMR方法研究了2,2′-(3,4 -四酸二酐)二苯甲酰氧基 -1,1′联萘的结构 ,并通过二维1H - 1H同核相关、13C - 1H异核相关及13C - 1H异核远程相关谱进一步地确定其1H谱和13C谱中各谱峰的归属 ,为同类化合物的表征提供了依据。
Resumo:
Molecule dynamics simulation was used on HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene), which is a discotic Liquid crystal. From analyzing the energy and displacement varying with the temperature, the phase transition temperature of PM6MPP can be predicted. The deviations of T-g, T-m and T-i due to the MD time scale are small enough that it should be possibly used to predict the material properties especially when more powerful computers are available.
Resumo:
Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters are a = b = 20.3 angstrom, c = 3.52 angstrom, = = 90 degrees, = 120 degrees. The core of HPT is not perpendicular to the column. The angle between a axis and HPT core plane is 9 degrees which cannot be seen in b-c projection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.
Resumo:
Lutetium(III) and lanthanum(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP), 3',5'-cyclic deoxyadenosine monophosphate (dcAMP) and 2',3'-cyclic adenosine monophosphate (2',3'-cAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. 2',3'-cAMP is converted to 3'-AMP and 2'-AMP, the ratio of 3'-AMP to 2'-AMP produced being 1.4.
Resumo:
The title compound, C24H24O3Si2, is a twofold symmetric silicocrown ether with the two dimethylsilyl groups attached to the O atoms of 1,1'-bi-2-naphthol, and bridged by another O atom.
Resumo:
合成了NdnSrFenO3n+1(n=1,2 ,3,∞ ) 系列复合氧化物 ,其中Nd3SrFe3O10 是首次合成 ,并研究了其晶体结构 ,IR谱以及 30 0~ 110 0K之间的电性质和磁性质。相对于NdSrFeO4 ,Nd2 SrFe2 O7中ab平面上的Fe O键较短而c轴方向的Fe O键较长 ;而NdFeO3中只有一种Fe O键 ,在 30 0~110 0K之间 ,NdSrFeO4 ,显反铁磁性行为 ,Nd2 SrFe2 O7表现为亚铁磁性 ,而Nd3SrFe3O10 和NdFeO3为顺磁性。随着n值的增大 ,该系列氧化物电阻率增大 ,这可能是系统四价Fe离子浓度减小的结果。
Resumo:
The aggregate structure of the discotic compound 2,3,6,7,10,11-hexakispentyloxytriphenylene (HPT) was studied both for the crystalline state and the liquid crystalline state by using electron crystallography and a molecular simulation approach. In the crystalline state, HPT was found to adopt an orthorhombic P-2212 space group with cell parameters a = 36.73 Angstrom, b = 27.99 Angstrom and c = 4.91 Angstrom. Molecular packing calculations were conducted to elucidate the molecular conformation and mutual orientational characteristics in the different states. Phase transitions and relationships are discussed from a structural point of view.
Resumo:
以1,4-萘醌为原料,经溴化、氰化、烷基化合成了1,4-二丙氧基-2,3-二氰基萘,用SiemensP4四圆衍射仪测得了晶体结构。合成方法简便,反应时间短,产率高。
Resumo:
用 Siemens P4四圆衍射仪,测得了1,4-二丙氧基-2,3-二氰基萘的晶体结构。晶体属单斜晶系,空间群为 C2/C。晶格参数 a=14.987(3)A,b=10.527(2),c=11.755(2),β=118.98°(3),晶胞体积 V=1622.4(6)3,Z=4,Dc=1.205Kg/m~3,μ(MoK_α)=0.079mm~(-1),F(000)=624,T=293(2)K_o晶体结构应用直接法,解出最后的偏离因子 R=0.0554[1425个Ⅰ≥2σ(Ⅰ)衍射点]。结构分析表明,萘环的1,4和2,3位碳原子上的氢原子分别被丙氧基和氰基所取代,由于取代基的引入使萘环的结构有所改变。