苯乙烯-马来酸酐共聚物的核磁共振分析

利用^1H NMR、^13C NMR及DEPT(无畸变极化转移增强)核磁共振技术研究了苯乙烯-马来酸酐共聚物(SMA)的序列结构和组成，并比较了几种核磁共振实验技术对分析SMA结果的准确性；实验表明^1H NMR是分析组成的简单、快速而有效的方法，DEPT谱进行序列结构计算准确度较高。     

二醋酸纤维素 -聚乙二醇接枝共聚物的核磁共振表征

用^1H NMR和^13C NMR核磁共振技术研究了二醋酸纤维素和聚乙二醇的接枝反应,并确定了^1H NMR和^13C NMR谱中各谱峰的归属,为证明二醋酸纤维素和聚乙二醇的接枝反应提供了依据。     

模型毒物急性毒性尿液核磁共振氨谱标记物的二阶段聚类分析

采用现代核磁共振技术，通过分析给药肝、肾损伤模型化合物异硫氰酸α-萘酯（灌胃150mg／kg体重）和二溴乙胺氢溴酸盐（腹腔注射250mg／kg体重）24h内Wistar大鼠尿液的^1H NMR谱，由尿液中内源性代谢物浓度变化研究了肝、肾模型毒物在大鼠体内的急性毒性。首次利用模式识别技术中的二阶段聚类分析方法解析大鼠尿液^1H NMR谱确定了模型化合物尿液^1H NMR标记物。结果表明，应用核磁共振和二阶段聚类分析相结合的方法，可提供模型化合物毒性比较清楚的认识。该方法也可用于金属化合物、中药及其它药物的毒性分类和预测研究以及建议各类靶向毒性的NMR标记物。     

Na4-CyDTA空间位阻的动态核磁共振研究

用动态核磁共振（DNMR）的方法研究了Na4-CyDTA乙羧基质子^1H—NMR谱随温度的变化关系，结果表明，常温下由于乙羧基旋转受到空间阻碍导致其^1H—NMR谱分裂为1组AB谱，随温度升高，AB谱的化学位移差减小．通过拟和化学位移差与温度的关系，计算出了Na4-CyDTA中阻碍乙羧基旋转的能垒为16．95kJ／mol．     

人体尿液代谢组NMR分析

利用固相萃取分离和核磁共振技术（nuclear magnetic resonance,NMR）对人体尿液中的代谢物进行了较为系统的研究。通过对人体尿液样品固相莘取后分离得到的五个组分^1H NMR,同核二维氢谱（correlation spectroscopy,COSY）和全相关谱（total correlation spectroscopy,TOCSY）,异核相关光谱（heteronuclear single quantum correlation,HSQC和Heteronuclear muptiple bond correlation,HMBC）,J-分解谱（J-resolved spectroscopic,J-RES）的谱图分析,解析出了74种化合物的^1H和^13C化学位移,并对一维^1H谱的多数谱峰进行了有效指认。     

含二氮杂萘酮单元双官能团化合物结构的波谱表征

在成功地合成了11个用于制备聚芳酰胺类聚合物的含二氮杂萘酮单元的双官能团化合物基础上,本实验用核磁共振波谱确定了各化合物的结构。用二维同核位移相关谱(gCOSY)、异核^13C-^1H-键相关谱(gHSQC)和异核^13C-^1H远程相关谱(gHMBC)完成了全部^1H和^13C NMR谱带的归属;首次报道了该系列衍生物的氢和碳原子的化学位移值。对其系列化合物的核磁共振波谱及红外光谱的特征进行了讨论。     

细胞内游离离子及离子通道的核磁共振研究

生物细胞内游离离子及离：子通道(Ca^2 、Mg^2 、Na^ 、K^ 以及Na^ ／Ca^2 和Na^ ／Li^ 交换等)在生理病理过程中起着重要作用。用于这些方面研究的生物核磁共振方法主要包括有：^31PNMR、^19NMR、^7Li NMR及^23Na NMR等。^31P NMR主要用于对细胞内小分子代谢物、pH及游离Mg^2 的分析测定；^19F NMR是利用氟代指示剂间接地测定细胞内游离Mg^2 和Ca^2 的浓度，进而对钙镁离子通道进行分析研究；^7Li NMR、^23Na NMR等方法分别用于研究Li^ 、Na^ ／Li^ 交换、Mg^2 ／Li^ 交换、Na^ 及K^ 等。为了更好地理解和阐释细胞内离子的调控机制，本文对近几年核磁共振技术在这些方面的应用进行了综述。     

联吡啶与铼、钌络合物的核磁共振谱分析

对2，2’—联吡啶—4，4’—二羧酸乙酯与过渡金属铼络合物(化合物1)和钌络合物(化合物2)的结构进行了核磁共振与电喷雾质谱(ESI—MS)的分析研究；利用^1H—^1H COSY、HSQC、HMBC等二维相关NMR谱淮确表征了化合物的结构，观测了远程偶合作用。     

NMR位移试剂Eu(fod)~4^-对锍盐^1H和^1^3C NMR的影响

合成了八种新的四氟硼酸二甲基苯基锍，用元素分析和核磁共振对其结构进行了表征。研究了以CDCl~3为溶剂，NMR位移试剂Eu(fod)~4^-对所合成锍盐的^1H和^1^3C NMR的影响。结果表明，Eu(fod)~4^-是一个对锍盐非常有效的位移试剂，且Eu(fod)~4^-对二甲基苯基锍盐之甲基的^1H和^1^3C NMR的位移呈线性关系。     

四氟菊酯的核磁共振法分析

采用^1HNMR、^13C NMR、无畸变增强极化转移实验(DEPT)、^1H—^1H相关谱(COSY)、^1H检测异核多量子相关谱(HMQC)、^1H检测的异核多键相关谱(HMBC)等方法，对四氟菊酯的^1H和^13C NMR谱信号进行了归属；并用奥氏核效应(NOE)差谱法确定了该化合物的立体结构，为其结构鉴定和生产过程中的质量控制提供了重要依据。     

Flow injection analysis NMR (FIA–NMR): a novel flow NMR technique that complements LC–NMR and direct injection NMR (DI–NMR)

Details of a new flow NMR technique, flow injection analysis NMR (FIA–NMR), are presented for the first time. This method blends some aspects of both liquid chromatography–NMR and direct injection NMR, and complements both. FIA‐NMR is shown to be useful as an analytical technique, especially for repetitive analyses, and may also prove useful in the analysis of combinatorial chemistry libraries. The feasibility of FIA‐NMR is demonstrated by the quantitative analysis of an over‐the‐counter pharmaceutical. Copyright © 2003 John Wiley & Sons, Ltd.     

光谱法分析乙丙共聚物的序列结构及链节比

用FTIR, 1 H NMR和 13 C NMR分析乙丙共聚物的序列结构与链节比. 通过对乙丙共聚物 1 H NMR, 13 C NMR和 13 C-1 H二维核磁共振谱的综合分析, 提出了与前人不同的归属, 并提出了不同位置碳原子积分面积相关性分析方法, 该方法避免了烦琐的理论计算, 可简便地得到乙丙共聚物的主要序列结构. 通过比较 1 H NMR和 13 C NMR计算乙丙共聚物中乙烯、 丙烯链节比, 表明可以用 1 H NMR代替 13 C NMR完成对乙丙共聚物中乙烯、 丙烯链节比的定量计算.     

核磁共振法研究固体表面上的吸附

应用JEOL FX-90Q NMR谱仪测定了吸附在NaY分子筛,氧化铝,二氧化硅上的四甲基硅烷和正己烷的核磁氢谱和碳谱.结果表明,在一些吸附体系的研究中,现有仪器适用于液体样品,以氢谱和碳谱比较发现碳谱在分辨率分方面较之氢谱有几个优点,顺磁杂质对谱线宽度有明显影响.在NaY分子筛上预先吸附氢以后再吸附乙烯,其吸附速率低于未吸附氢的样品.     

RNA unrestrained molecular dynamics ensemble improves agreement with experimental NMR data compared to single static structure: a test case

Nuclear magnetic resonance (NMR) provides structural and dynamic information reflecting an average, often non-linear, of multiple solution-state conformations. Therefore, a single optimized structure derived from NMR refinement may be misleading if the NMR data actually result from averaging of distinct conformers. It is hypothesized that a conformational ensemble generated by a valid molecular dynamics (MD) simulation should be able to improve agreement with the NMR data set compared with the single optimized starting structure. Using a model system consisting of two sequence-related self-complementary ribonucleotide octamers for which NMR data was available, 0.3 ns particle mesh Ewald MD simulations were performed in the AMBER force field in the presence of explicit water and counterions. Agreement of the averaged properties of the molecular dynamics ensembles with NMR data such as homonuclear proton nuclear Overhauser effect (NOE)-based distance constraints, homonuclear proton and heteronuclear ¹H–³¹P coupling constant (J) data, and qualitative NMR information on hydrogen bond occupancy, was systematically assessed. Despite the short length of the simulation, the ensemble generated from it agreed with the NMR experimental constraints more completely than the single optimized NMR structure. This suggests that short unrestrained MD simulations may be of utility in interpreting NMR results. As expected, a 0.5 ns simulation utilizing a distance dependent dielectric did not improve agreement with the NMR data, consistent with its inferior exploration of conformational space as assessed by 2-D RMSD plots. Thus, ability to rapidly improve agreement with NMR constraints may be a sensitive diagnostic of the MD methods themselves.     

1.5T核磁共振弛豫时间分析仪的研制及其潜在应用

介绍了国产1.5T核磁共振弛豫时间分析仪的基本组成、性能指标,研发过程中攻克的技术难题。该仪器主要由磁体部分、电子部分、软件部分组成,具有体积小、信噪比高、检测无损、使用和维护简便和造价低廉等优点。同时对该系统磁体频率和磁信号的稳定性进行了相关的测试,结果表明该系统稳定可靠。该仪器的磁场强度增加到1.5T,在同等外界条件和环境下,信噪比增加约为0.5T系统的10倍,检测灵敏度大幅度提高;该仪器为食品品质鉴定、食品安全检测、医学诊断、生物标志物的大规模筛选等生化分析提供一个全新的途径。     

13C and 15N NMR studies of iron-bound cyanides of heme proteins and related model complexes: sensitive probe for detecting hydrogen-bonding interactions at the proximal and distal sides

Studies of the 13C and 15N NMR paramagnetic shifts of the iron-bound cyanides in the ferric cyanide forms of various heme proteins containing the proximal histidine and related model complexes are reported. The paramagnetic shifts of the 13C and 15N NMR signals of the iron-bound cyanide are not significantly affected by the substitution of the porphyrin side chains. On the other hand, the paramagnetic shifts of both the 13C and 15N NMR signals decrease with an increase in the donor effect of the proximal ligand, and the 13C NMR signal is more sensitive to a modification of the donor effect of the proximal ligand than the 15N NMR signal. With the tilt of the iron-imidazole bond, the paramagnetic shift of the 13C NMR signal increases, whereas that of the 15N NMR signal decreases. The hydrogen-bonding interaction of the iron-bound cyanide with a solvent decreases the paramagnetic shift of both 13C and 15N NMR signals, and the effect is more pronounced for the 15N NMR signal. Data on the 13C and 15N NMR signals of iron-bound cyanide for various heme proteins are also reported and analyzed in detail. Substantial differences in the 13C and 15N NMR shifts for the heme proteins can be explained on the basis of the results for the model complexes and structures around the heme in the heme proteins. The findings herein show that the paramagnetic shift of the 13C NMR signal of the iron-bound cyanide is a good probe to estimate the donor effect of the proximal imidazole and that the ratio of 15N/13C NMR shifts allows the hydrogen-bonding interaction on the distal side to be estimated.     

Structure elucidation and NMR spectral assignment of five new xanthones from the bark of Garcinia xanthochymus

Five new xanthones, namely Garcinexanthones A-E (1-5), were isolated from the barks of Garcinia xanthochymus. Their structures were elucidated by spectral analysis, primarily NMR, MS, and UV. The complete assignments of the (1)H NMR and (13)C NMR chemical shifts for the compounds were achieved by using 1D and 2D NMR techniques, including DEPT, HSQC, and HMBC NMR experiments.     

Fragment Screening and Fast Micromolar Detection on a Benchtop NMR Spectrometer Boosted by Photoinduced Hyperpolarization

Fragment-based drug design is a well-established strategy for rational drug design, with nuclear magnetic resonance (NMR) on high-field spectrometers as the method of reference for screening and hit validation. However, high-field NMR spectrometers are not only expensive, but require specialized maintenance, dedicated space, and depend on liquid helium cooling which became critical over the recurring global helium shortages. We propose an alternative to high-field NMR screening by applying the recently developed approach of fragment screening by photoinduced hyperpolarized NMR on a cryogen-free 80 MHz benchtop NMR spectrometer yielding signal enhancements of up to three orders in magnitude. It is demonstrated that it is possible to discover new hits and kick-off drug design using a benchtop NMR spectrometer at low micromolar concentrations of both protein and ligand. The approach presented performs at higher speed than state-of-the-art high-field NMR approaches while exhibiting a limit of detection in the nanomolar range. Photoinduced hyperpolarization is known to be inexpensive and simple to be implemented, which aligns greatly with the philosophy of benchtop NMR spectrometers. These findings open the way for the use of benchtop NMR in near-physiological conditions for drug design and further life science applications.     

NMR Studies of polymeric materials - an overview

NMR has been used extensively in studies of synthetic polymers. The approaches employed may require solution NMR, solid state NMR, or NMR imaging. In each case, different techniques and analytical methodologies have been devised to facilitate experimentation or to maximize information output. These techniques are not mutually exclusive and often provide complementary information. A selective review is made herewith of polymer/NMR studies, with emphasis on the contributions made at NMR symposia held in Detroit in October, 1993 as part of the 20th FACSS meeting.