342 resultados para H-1-NMR
Resumo:
Three new bimetallic complexes were synthesized and crystalized by reactions of (CF3CO2)(3)Ln With R(1) AlR(2)(Ln=Nd and Y, R(1)=H, R=i-C4H9; Ln=Eu, R=R(1)=C2H5) in tetrahydrofuran solution, and their crystal structures were determined using a X-ray diffraction method. The structures and the questions on valence state and noncoplanarity in the structures were confirmed and cracked by means of H-1 NMR and C-13 NMR spectra, especially by C-13-H-1 COSY 2D NMR technique. A general formula of molecules of the three rare earth complexes was defined as follows: [(mu-CF3CO2)(2)Ln(mu-CF3CHO2)AlR(2) . 2THF](2) A mechanism on the formation of the new complexes was also proposed through the following five steps: alkylating, beta-elimination (or hydrogenation), hydrogen transfer, linkage and association. Both Y-Al and Eu-Al complexes function as a catalyst in polymerization of MMA and ECH. The polymer obtained from the first monomer is mainly syndiotactic chain structure and the polymerization of the last monomer shows higher catalytic activity. The Y-Al complex also capable of ring-opening polymerization of THF in case of adding-vary small amount of ECH and a oxonium ion mechanism of THF polymerization was suggested from the analysis of THF polymer terminal.
Resumo:
A new chiral liquid crystal with Schiff base group has been prepared, The structure of liquid crystal was confirmed by elementary analyses and H-1 NMR. Its phase transition was investigated by polarized optical microscope, DSC and temperature-depending FTIR spectra. The results showed that the chiral Schiff base showed monotropic phases behavior in certain temperature range, the phase sequence is I-N-*-S-B-S-G-K on the cooling sequence.
Resumo:
The compound [FeCp(Tol)](2)[Ni(mnt)(2)] has been prepared from [FeCp(Tol)]AlCl4 and Na-2[Ni(mnt)(2)]. This new organometallic radical ionic salt has been characterized by elemental analysis, IR, H-1 NMR and mass spectroscopy. The X-ray structure of the compound shows there are segregated cation and anion stacks in the perpendicular directions, The molecular anions form a zig-zag stacking along the b axis, and between every two neighbouring anion planes a methyl group of the cation is inserted. This gives rise to a long spacing of 6.87 Angstrom, between the anion planes. The cations stack along the c axis, with the closest spacing of 3.457 Angstrom between the cyclopentadienyl plane and the neighbouring toluene plane, which is shorter than the sum of Van der Wall's radii. Conductivity measurements showed the compound as a semiconductor with a room temperature conductivity of 1.6 X 10(-4) Scm(-1).
Resumo:
The interaction of [(C(5)H(4)R)(2)NdCl.2LiCl] (R = H, Bu(t)) with one equivalent of Li[(CH2)(CH2)PPh(2)] in refluxing tetrahydrofuran gave the purplish-blue complex [(C(5)H(4)R)(3)NdCH2P(Me)Ph(2)] in 50% yield. The compounds have been fully characterized by analytical, spectroscopic and X-ray diffraction methods. Variable temperature P-31{H-1} NMR spectroscopy indicated the existence of the following equilibrium: [(C(5)H(4)R)(3)NdCH2P(Me)Ph(2)] + THF reversible arrow (C(5)H(4)R)(3)Nd(THF) + CH2=P(Me)Ph(2). At room temperature, the exchange between the coordinated and free ylide ligand is slow on the NMR time scale.
Resumo:
New copolyether sulfones containing 2,6-bis(p-oxo-benzylidene)cyclohexanone and 2,6-bis(o,p-dioxo-benzylidene)cyclohexanone moieties were prepared in the conventional literature manner by condensing the dipotassium salts of 2,6-bis(p-hydroxybenzylidene)cyclohexanone (III), 2,6-bis(o,p-dihydroxybenzylidene)-cyclohexanone (V), and 2,2-bis(p-hydroxyphenyl)propane (Bisphenol A, VII) with 4,4'-dichlorodiphenyl sulfone (VI), or by condensing the dipotassium salts of III and VII with a new benzylidene cyclohexanone sulfone macromer (X). Finally, the polycondensation reaction of sulfonyl bis(p-benzaldehydeoxo-p-phenylene) (IX) with cyclohexanone leads to an unsaturated copolymer (XVI). The resulting copolyether sulfones were confirmed by IR, H-1-NMR, viscometry, elemental analysis, thermooptical (TOA), x-ray, and thermogravimetric (TGA) measurements.
Resumo:
Polymers of methyl-iso-propyl fumarate, di-iso-propyl fumarate, di-t-butyl fumarate, di-s-butyl fumarate, di-s-amyl fumarate and di-cyclo-hexyl fumarate were prepared by radical polymerization. The structures of the polymers were examined by H-1-NMR, C-13-NMR and WAXD. Some properties of the polymers, including thermal properties, were examined.
Resumo:
Reaction of lanthanide trichlorides with two equivalents of sodium t-butylcyclopentadienide in THF gave rise to the bis(t-butylcyclopentadienyl)lanthanide chloride complexes [(Bu(t)Cp)2LnCl]2 (Ln = Pr, Gd, Er), which were characterized by elemental analysis, IR and H-1 NMR spectroscopy. In addition, the crystal structures of [(ButCp)2PrCl]2 (1) and [(ButCp)2GdCl]2 (2) were determined by single crystal X-ray diffraction at room temperature. The coordination number for Pr3+ and Gd3+ is 8 and the bond lengths Pr-Cl and Gd-Cl are 2.864(2) and 2.771(3) angstrom, respectively. The structural studies showed the complexes to have C2h symmetry.
Resumo:
New bis (2-methoxyethylcyclopentadienyl) yttrium and ytterbium tetrahydroborates (Ln = Y, 1; Yb, 2) have been synthesized in good yield by the reaction of bis (2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln = Y, Yb) with sodium borohydride in THF at room temperature. The title complexes were characterized by elemental analyses, MS, H-1 NMR and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. 1 crystallizes from THF-n-Hexane in space group Pna2(1) with unit cell parametert: a = 1.2390(3), b = 1.1339(2), c = 1.1919 (2) nm and V = 1.6745(6) nm3 with z = 4 for D(c) = 1.39 g.cm-3.The structure was solved by direct method and refined to final R = 0.061 (for 1730 observed reflections). The Space group of 2 is Pna2(1) with unit cell parameters: a = 1.2399(6), b = 1.1371(5), c = 1.1897(2) nm and V = 1.6773(1) nm3 with z = 4 for D(c) = 1.72 g.cm-3, R = 0.038 (for 2157 observed reflections). The X ray structures and IR reveal the bidentate yttrium and ytterbium tetrahydroborate complexes with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.
Resumo:
The five complexes (RC5H4)2M(S2CNBz2)Cl (R = H, CH3; M = Ti, Zr, Hf; Bz = CH2C6H5) have been prepared by the reaction of (RC5H4)2MCl2 with anhydrous sodium salts of dibenzyldithiocarbamate in refluxing CH2Cl2. These complexes have been characterized by elemental analysis, IR and H-1 NMR. X-ray crystal structure determination of Cp2Zr(S2CNBZ2)Cl shows the molecule has a five-coordinate bent metallocene geometry in which the zirconium atom is attached to two eta-5-C5H5 groups, one bidentate dibenzyldithiocarbamate ligand and one chlorine [Zr-Cl, 2.549(1) angstrom; Zr-S, 2.734(1), 2.667(1); Cl-Zr-S, 137.6(1)-degrees and 73.3(1)-degrees; S-Zr-S, 64.3(1)-degrees]. The catalytic system Cp2Ti (S2CNBZ2)Cl-NaH exhibits high initial catalytic activity of hydrogenation of hexene-1 under mild conditions.
Resumo:
The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.
Resumo:
海洋高分子有机物在水生态系统中具有很重要的作用。以生化稳定性为特征的腐植质能促进生物细胞的呼吸和营养盐吸收;腐化过程使生化反应的中部分生物转化为相对的物质从而增加生态系统中有机物的稳定性;腐植质还参与液-液、液-固和气-液界面过程对许多微量元素的生物地球化学循环有很大的影响。论文首次用GDX-102树脂从硅藻代谢产物和分解产物中分离提取腐植质(EHS、DHS)以及乙醇可溶物(EES、DES)。用~1H-NMR、IR和紫外光进行结构分析并同海水腐蚀植质(HS)和乙醇可溶物(ES)进行比较。在测定~3H-NMR谱时,样品先在加有NaOD和D_2O溶液中溶解50天,结果得到结构信息十分丰富的谱图。HSEHS和DHS经碱水解后,许多小分子(如甲酸、甲醇、醋酸等)从大分子网络中释放出来,在~1H-NMR谱中出现许多离散尖峰,反映了它们前体物质的相似性。HS、EHS、和DHS都含有较多的高支链烷烃、碳水化合物和氨基酸结构及少量的芳烃和杂环化合物。另外,EHS和DHS中含有许多活性基团如腈基(可能是蛋白质、核本和卟啉的分解产物)、参键等,说明其仍处于腐植化过程中。结果表明,浮游植物分解产物和代谢产物是海水植质的重要来源。~1-NMR和IR谱表明,ES、EES和DES结构差别较大。ES和DES含有大量高支链烷烃(可能来源于藻类中的类脂化合物),而在EES中烷烃含量相对很少。ES、EES和DES具有不同类型的羰基(IR谱上的吸收峰分另为1720cm~(-1)、1750cm~(-1)、1680cm~(-1));另外,三者与氧、氮相连的α-碳上的质子类型也有很大不同。EES的低含量高支链烷烃(高支链烷结构不易被细菌降解)以及DES中含有复杂的降解产物组份表明它们潜在的不稳定性。海洋环境中广泛存在着松散的絮状聚合物--海洋雪。海洋雪是光合作用过程和营养盐循环的重要场所,作为大洋中特殊微环境--碎屑小生境具有和周围水体明显不同的生化性质,如有很高的新陈代谢活性,在海洋的物质、能量流动中起着重要作用。实验研究了碎小生境演分过程中特殊营养盐迁移过程和脱氢酶活性的变化,认为碎聚合物表面不仅有微生物群落的演替,而且存在非平衡过程的连续变化。当碎表面有机物氧化,O_2被消耗碳出现氧化还原电位梯度时,在时间分布上NO_3~-、SO_4~(2-)、CO_3~(2-) 可分别成为缺微区代谢过程的最终电子受体。而碎小生境氧化还原电位梯度的存在使一些要求不同氧化还原势的过程紧靠在一起进行,即在碎屑表面分布上存在不同的电子最终受体。具有特殊性质的碎屑小生境允许一些在周围水体中不能进行或受抑制的特殊营养盐迁移过程(如固氮、硝化、反硝化、氨化甚至发酵)在碎屑表面进行。对于碎屑小生境非平衡态过程的改变,作为一种适应,微生群落重新调节新陈代谢,在分叉点附近,脱氢酶活性增大。因此,碎屑小生境是一个时空有序的半封闭结构。论文还对碎屑小生境的涨落和稳定性机制作了探讨。
Resumo:
The structure of a polysaccharide from the red seaweed, Porphyra capensis, growing along the coast of Namibia and South Africa was investigated. Algae growing at different sites and collected at different times gave a polysaccharide extract with similar chemical components. FTIR and NMR spectral analysis showed that the polysaccharide from P. capensis had a typical porphyran structure. It has the linear backbone of alternating 3-linked beta-D-galactose and 4-linked alpha-L-galactose-6-sulfate or 3,6-anhydro-alpha- L-galactose units. The ratio of alpha-L-galactose-6-sulfate and the 3,6-anhydrogalactose is 121, as reflected by a H-1 NMR spectrum. A high degree of methylation occurred at the C-6 position of the D-galactose units. The degree of methylation was 0.64 for the D-galactose residues. (C) 2005 Elsevier Ltd. All rights reserved.
Resumo:
Novel microbiocides 2-(hydroxymethyl)benzo[d)isothiazol-3(2H)-one (7) and (3-oxobenzo[d]isothiazol-2(3H)-yl)methyl benzencarboxylates (11a-c) were synthesized in good yields, and their structures were characterized by means of H-1 NMR, MS, and elemental analysis. The new compounds were tested preliminarily in laboratory assays against the aquicolous bacteria including Escherichia coli, Staphyloccus aurueus, Vibrio alginolyticus, Aeromonas hydrophila, and Bacillus subtilis. The results show all the synthesized compounds have good antimicrobial activity. The antimicrobial activity of all the tested compounds against all test bacteria is >96.6% at the concentration of 10(-2) mg mL(-1). These compounds can be further developed for effective microbiocides in the future.
Resumo:
Four novel triazole compounds containing thioamide group were designed and synthesized by using triazole, phenyl isothiocyanate and aryl ethyl ketone as raw material. Their structures were conformed by elemental analysis, H-1 NMR, IR and MS spectra. The crystal structure of 1-[1-anilinothiocarbonyl-1-(4-fluorobenzoyl)methyl]-1,2,4-trizole has been determined by X-ray diffraction analysis. The preliminary bioassays have shown that the title compounds exhibit certain antifungal activity.
Resumo:
Nine novel triazole compounds containing ester group were designed and synthesized. Their structures were confirmed by elemental, H-1 NMR and IR analyses, and optimized by means of DFT (Density Functional Theory) method at the B3LYP/6-31G* level. Based on the quantum-chemical calculation results and the Pearson coefficients between FA and quantumchemical parameters, V, LogP, MR and E-HOMO are shown to be the important relative factors which affect FA of the title compounds.