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1991年, 第8卷, 第1期 刊出日期:1991-03-05
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β-萘黄酮和β-二氢萘黄酮类化合物的13C-NMR研究
王动, 高从元, 吕以仙, 蔡孟深
波谱学杂志, 1991, 8(1): 11-18.
本文研究了14种β-萘黄酮和β-二氢萘黄酮类化合物的13C化学位移,发现其变化规律和单黄酮无大差异。通过COSY,HETCOR,HETCOLOC等2D-NMR谱和PBB,DEPT,QUAT,SELDEPT等碳谱实验指定了它们的碳的全部归属。
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取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构Ⅱ.取代基效应方法
周子南, 田文晶, 吴盛容, 张建国, 裴奉奎
波谱学杂志, 1991, 8(1): 55-61.
本文提出了一种解析乙烯-α-烯烃共聚物的13C NMR谱的取代基效应方法,它揭示了存在于共聚物序列结构与13C谱之间的对应关系,并对这种关系进行了系统的阐述。文章中首次按上述对应关系明显与否将共聚物13C谱分成两类,并给出进行分类的三种判据:SCS参数,共单体均聚物的13C谱,以及取代基的电性。文章最后比较了取代基效应方法与Grant-Paul方法的异同。
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THE APPLICATIONS OF NUCLEAR SPIN RELAXATION TO POLYMER DYNAMICS AND INTERMOLECULAR INTERACTIONS
Yan Xin, Wang Dehua, Qian Baogong
波谱学杂志, 1991, 8(1): 62-62.
The correlation functions of the side-groups and side-chains of polymers are obtained for nuclear spin relaxation if the segmental motion of the polymers is described by VJGM model, these functions are derived from unequal two-side and three-site jump internal rotation, diffusion internal rotation, restricted internal rotation and multiple internal rotation. The corresponding spectral density functions are also given, and these functions are used to interpret the nuclear spin relaxation data of the side-groups of some polymers. The average spectral density functions of side-groups are derived under the magic angle spinning, the correlation times and diffusion coefficients of the side-groups of crosslinked poly (methyl methacry-latcs) and solid poly(vinylbutyral) are obtained by using these average spectral density functions. The multiphase structures of nylon 6, poly (ethylenc glycol) and its complexes are investigated with cross-polarization and magic angle spinning techniques. Three methods using nuclear spin relaxation are presented for studying the intermolecular interaction between polymers and solvents:First, the molecule of tetrachloromethane is used as a "probe" to detect the intermolecular interaction between polymers and tetrachloromethane; Second, the contribution to the spin-lattice relaxation of the quaternary carbons due to the intcrmolecular dipolar interaction is used to calculate the poly (butyl methacrylate)-solvent interaction variables; Third, the intermolecular interaction variables are obtained from the intermolecular heteronuclcar crossrelaxation rates. The heteronuclear cross-relaxation rates are also used to determine the distances among heteromuclei, the general formula for Calculating distances is derived, the experimental results for polymers testify that the formula is correct. It can be shown with the two-dimensional heteronuclear Overhauser effect technique that the dipolar interaction between the quaternary carbons in polymers and their nearest protons dominates the spin-lattice relaxation of the quaternary carbons. The two-dimensional cadmium-113-proton Overhauser effect spectra of a few cadmium compounds are first reported.
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取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构Ⅲ.定量分析
周子南, 田文晶, 吴盛容, 张建国, 裴奉奎
波谱学杂志, 1991, 8(1): 63-72.
本文在分析乙烯-α-烯烃共聚物序列结构时,把代表共单体反接单元的亚甲基(CH2)βγ和γδ分别归属给了二元组VV和三元组EEV。与此同时,CH2-δδ和δδ+归属给了二元组EE。表征乙烯长序列的CH2-δ+δ+分属二元组EE和三元组EEE,对应峰强度在EE和EEE之间的分配是处理序列分布的关键。在本文中运用序列结构的Bovey关系和Randall统计进行演算,求得了修正值△的数学表达式,严格解和近似解。在规则链条件下得到的近似解与G.J.Ray的结果完全相同。当共单体含量较少时,谱峰强度Iδ+δ+的分配接近相等。 在二元组和三元组的水平上,乙烯-α-稀烃共聚物的13C NMR谱中共有十三个峰,属于CH2的有十个,属于CH的有三个。利用这些谱峰的强度数据可以建立一套计算公式,由此提供共聚物序列结构的全部信息。因此这是一个研究乙烯-α-烯烃共聚物序列结构的普适方法。
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水溶液中甘氨酰替亮氨酸与Ho(ClO43和Yb(ClO43相互作用的NMR研究
任吉民, 牛春吉, 裴奉奎, 王文韵, 倪嘉韵
波谱学杂志, 1991, 8(1): 89-98.
本文用13C NMR方法研究了水溶液中三价顺磁性稀土离子Ho3+和Yb3+与二肽甘氨酰替亮氨酸之间的相互作用。对稀土诱导位移中的接触位移和偶极位移进行了分离。实验表明,与羧基相连的碳核所受的接触作用很大,因此不能把镱诱导的位移直接用于肽的构象分析。在水溶液中,肽通过羧基与稀土离子配位,在弱酸性条件下肽键和氨基均不参与配位。根据结构因子确定了肽在溶液中的构象,结果表明,分子片段C1-C2-C5-C6,C2-N-C3-C4和C2-C5-C6-C8为反式,而C2-C5-C6-C7和C1-C2-N-C3成旁式。
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一种精密的边限振荡器型NQR谱仪及其应用
房德慧, 刘德海, 郑小利, 张彼得
波谱学杂志, 1991, 8(1): 123-130.
本文介绍一种精密的场效应管边限振荡器型核四极矩共振(NQR)谱仪。工作频率范围14MHz~35MHz,分段连续可调。这种谱仪的灵敏度高、波形失真小。在室温下,多晶粉未状氯酸钾样品中35Cl的NQR频率测量精度大约3×10-6。重结晶样品中35Cl的NQR谱一次微分信号信噪比S/N ≥ 150。用该谱仪对KClO3、NaClO3、NaCl样品进行测试,得到氯的同位素35Cl和37Cl的四极耦合常数比(eQq35Cl/(eQq37Cl的实测值分别为1.2687363、1.2687306、1.2687361。在77K到393K温度区间测量了氯酸钾多晶粉未状样品中35Cl的NQR共振频率和温度的关系,在冰水混合温度附近,温度每变化0.1K,NQR频率的变化是478Hz。
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