Chromatographic separation and C-13 NMR characterization of aromatic diester-diacids isomers

Reverse phase high performance liquid chromatography (HPLC) was used to separate and quantify aromatic diester-diacids isomers which arise from the opening selectivity of anhydride rings towards methanol. C-13 NMR spectroscopy was a supplementary tool to characterize the isomer structure. It was found that a meta-position attack is slightly preferred in pyromellitic dianhydride (PMDA), while the preferred position of an attack in bridged dianhydrides is determined by the chemical nature (donors or accepters) of the bridged group. The stronger its electron-withdrawing abilities, the lower the probability of a meta-position attack.

Synthesis and structure of 1:1 complex of ethylphenyltin dichloride with N-4-methoxyphenyl-2-hydroxynaphthylideneimine

A novel organotin complex, EtPhSnCl(2) . 2HOC(10)H(6)CH = NC6H1OCH3 was synthesized, and its crystal structure was determined by X-ray diffraction method. The crystal is triclinic, belonging to space group, with unit cell parameters a = 1.150 8(5) nm, b = 1. 153 1(5) gm, c = 1. 004 6 (3) nm, alpha = 94. 15 (3)degrees, beta = 115.47 (3)degrees, r = 85. 94 (4)degrees, V = 1199 7(1) nm(3), Z=2, D-c=1.68 g/cm(3), mu=13. 20 cm(-1), F(000)=618 for 4 131 reflections tions. R=0. 047, R(w)=0. 047. The ligand coordinates to tin atom via phenolic oxygen atom. The complex has a distored trigonal bipyramidal structure, the phenolic oxygen atom of the ligand and one of two chlorine atoms occupy the axial position. The distance between noncoodinated nitrogen atom with phenolic oxygen atom is 0. 257 4 nm, which indicates that the intramolecular hydrogen bond of Schiff base ligand is retained in the complex.

~(13)C核磁共振波谱模拟的研究

近年来，随着计算机技术的发展，C-13 NMR技术取得巨大的进步，并获得了与日俱增的广泛应用。目前，已成为化学、化工、生物、医学等领域不可缺少的分析技术。C-13 NMR波谱模拟在有机化合物结构自动解析中起着极为重要的作用，它能帮助科学家们对复杂的化合物进行结构解析，并对测定的化合物的化学位移进行验证。本论文在该领域进行了很多有意义的尝试，工作的目的是采用多元统计方法为化合物的C-13 NMR波谱模拟建立相关数学模型，并取得了一些有意义的结果。主要工作如下：1. 对饱和烷烃类化合物进行了~(13)C NMR波谱模拟，通过使用校正的分子连接性指数和几何参数，取得了比较满意的结果，其结果比Crant和Paul的烷烃模拟要好。2. 对环烷烃类化合物进行了~(13)C NMR波谱模拟，得到了具有较好预测能力的相关数学模型。3. 对饱和醇类化合物进行了~(13)C NMR波谱模拟，通过提取共振碳的拓扑指数、电荷参数和几何参数，构造了比较满意的数学模型。4. 对脂肪胺类化合物进行了~(13)C NMR波谱模拟，通过使用拓扑指数、电荷参数和几何参数，获得了比较好的相关数学模型。5. 对饱和醛酮类化合物进行了~(13)C NMR波谱模拟，通过使用拓扑指数、电荷参数和几何参数，获得了比较好的相关数学模型。

几种典型固体聚合物体系的~（13）C自旋－晶格弛豫特性

用固体高分辨ＮＭＲ系统地研究了几种典型的均聚物，共聚物，聚合物共混物以及用接枝共聚物增容的不相容聚合物共混体系的１３Ｃ自旋－晶格弛豫特性。研究结果表明：１３Ｃ自旋－晶格弛豫时间（Ｔ１（Ｃ））是表征固体聚合物体系的很有用参数，它能提供有关本体聚合物微观形态结构的信息，并可望建立聚合物的微观结构与宏观性能的关系，它不仅能准确无误地反映共混体系中可能存在的各种相互作用，而且能定性地给出相互作用的大小和准确地指明相互作用产生的位置，因而为揭示共混体系的相容机理提供了最直接的证据，另外Ｔ１（Ｃ）还能给出增容剂对不相容共混体系的增容作用和增容机制的直接实验证据

~(13)C NMR研究稀土柠檬酸配合物的溶液配位结构

用稀土离子诱导位移和顺磁弛豫时间测定等NMR方法研究了稀土柠檬酸配合物在pH7.4的溶液中的配位结构.结果表明稀土离子通过3-羟基和3-羧基与柠檬酸配体形成1:2的配合物,两个端羧基没有参与配位.通过计算稀土离子和柠檬酸配体中各个碳原子间的空间距离的相对比,建立了稀土离子与柠檬酸配体配位的新模式.

茂锆载体催化剂下的乙烯／辛烯共聚及聚合物的~（13）C NMR研究

茂锆载体催化剂下的乙烯／辛烯共聚及聚合物的~（１３）ＣＮＭＲ研究刘胜生，于广谦，黄葆同（中国科学院长春应用化学研究所长春１３００２２）关键词茂锆载体催化剂，共聚，序列分布，~（１３）ＣＮＭＲ由于茂锆催化剂具有高活性，单一活性中心等特点［１，２］，并且能...

H-1 and C-13 NMR studies of TTHA complexes with diamagnetic rare earth ions

TTHA complexes with diamagnetic rare earth ions (La3+, Y3+ and LU(3+)) were studied by H-1 and C-13 NMR spectroscopy. A symmetric structural model was suggested for La(TTHA) complex and an asymmetric model for Y(TTHA) and Lu(TTHA) complexes. The complex formation was dependent on the pH value of the solution. The interactions of La(TTHA) with the additional metal ions (La3+, Y3+ and Ca2+) were relatively weak, but relatively strong for that of Lu(TTHA) with the additional Lu3+.

A new topological index for the Changchun institute of applied chemistry C-13 NMR information system

A method to assign a single number representation for each atom (node) in a molecular graph, Atomic IDentification (AID) number, is proposed based on the counts of weighted paths terminated on that atom. Then, a new topological index, Molecular IDentification (MID) number is developed from AID. The MID is tested systematically, over half a million of structures are examined, and MID shows high discrimination for various structural isomers. Thus it can be used for documentation in the Changchun Institute of Chemistry C-13 NMR information system.

掺Ce~（3＋）、Gd~（3＋）、Tb~（3＋）的CaLaB_7O_（13）的光

采用固相反应法合成了接Ｃｅ３＋、Ｇｄ３＋、Ｔｂ３＋的ＣａＬａＢ７Ｏ１３，并测定了它们的光谱．在Ｃｅ３＋的光谱中发现文献中尚未报导的３１７ｎｍ激发峰和２９３ｎｍ发射峰．２９３发射属于不常见的５ｄ能带中次最低能级向基态的跃迁，并随着Ｃｅ３＋离子浓度增加而变弱，当掺杂浓度大于０．１ｍｏｌ时，２９３ｎｍ发射峰消失.

聚丙烯腈热裂解产物的ESR和固体￣（13）CNMR研究

用电子自旋共振（ＥＳＲ）和固体￣（１３）ＣＮＭＲ研究了聚丙烯腈（ＰＡＮ）在不同裂解温度（Ｔ＿Ｐ）下的结构变化，当Ｔ＿Ｐ从２５０℃增加到６００℃，ＥＳＲ信号线形没有变化，ｇ值与Ｔ＿Ｐ无关，ΔＨ＿（ＰＰ）减小，自旋浓度（Ｎ＿Ｓ）开始增加，Ｔ＿Ｐ进一步升高，Ｎ＿Ｓ又减少．￣（１３）ＣＮＭＲ谱指出在不同Ｔ＿Ｐ下谱峰发生很大变化，与另文报道的红外及Ｘ－射经衍射结果一致，随Ｔ＿Ｐ升高，ＰＡＮ逐渐脱去小分子形成具有环化共轭结构的产物．

DSC AND C-13 NMR-STUDIES OF ETHYLENE-PROPENE COPOLYMERS PREPARED BY A HIGHLY-ACTIVE AND STEREOSPECIFIC CATALYST

Ethylene-propene copolymers (EPR) were synthesized at different feed compositions using a highly active and isospecific MgCl2-supported Ti-based catalyst. The thermal behavior of EPR was studied by differential scanning calorimetry, the heterogeneity by f

SEQUENCE-ANALYSIS OF FLUORINE-CONTAINING POLYARYLETHERSULFONE COPOLYMERS BY C-13-NMR

HexafluorobisA polyethersulfone-cardo polyethersulfone, random and block copolymers with different segment lengths were synthesized by a reaction of 4,4'-(hexafluoroisopropylidene)diphenol and 3,3'-bis(4-hydroxyphenyl)-1-isobenzopyrrolidone with bis(4-chl

对甲基酚醛树脂热裂解产物的固体~（13）CNMR

对甲基酚醛树脂热裂解产物的固体~（１３）ＣＮＭＲ谢德民，张建国，王存国，王荣顺（东北师范大学化学系，长春，１３００２４）关键词对甲基酚醛树脂，裂解，固体~（１３）Ｃ，ＮＭＲ酚醛树脂经热裂解制备的聚并苯导电材料在空气中稳定，由裂解温度可控制碳化程度，其本...

丙烯／长链α－烯烃共聚物的~（13）C—NMR和红外光谱法测定组成

丙烯／长链α－烯烃共聚物的~（１３）Ｃ—ＮＭＲ和红外光谱法测定组成陈辉，王建国，景凤英，庞德仁，黄葆同（中国科学院长春应用化学研究所，长春，１３００２２）关键词丙烯／长链α－烯烃共聚物，（１３）~Ｃ—ＮＭＲ，红外光谱法，组成测定聚丙烯（ＰＰ）作为通用塑...

谷胱甘肽与稀土离子作用的~(13)C NMR研究

本文利用顺磁稀土离子的诱导化学位移变化的性质,研究了多官能团配体谷胱甘肽(GSH)与稀土的配位作用.在水溶液中GSH通过分子两端的羧基负离子与稀土形成遥爪配位结构.谷氨酸端和甘氨酸端羧基与Eu~(3+)的配位稳定常数分别为12.5±0.1L/mol和100.0±0.5L/mol.从~(13)C化学位移的pH变化曲线求得谷氨酸端和甘氨酸端羧基解离的pK_a值分别为2.20±0.02和3.50±0.04.对Dy~(3+)、Ho~(3+)、Er~(3+)、Tm~(3+)和 Yb~(3+)作用下,GSH的~(13)C位移数据分析表明,配体与这些离子形成同构的配合物,分子两端羧基均可能以双齿形式与稀土配位.