氨基酸、肽-雌甾衍生物的13C-NMR研究

本文研究了八个新化合物-氨基酸、肽-雌甾衍生物的¹³C-NMR谱,讨论了谱蜂的特征,并借助于¹³C-NMR谱确证了此类新化合物的形成。     

8,2'-O-环化-9β-D-腺嘌呤阿拉伯糖苷的NMR及结构研究

8,2'-O-环化-9β-D-腺呤阿拉伯糖苷是阿糖腺苷合成过程中的一个关键性中间体,该化合物的NMR数据只有¹H-NMR谱的糖环1'位质子化学位移和偶合常数的报道,¹³C-NMR谱未曾报道。本文用2D-NMR、NOE-DIF等技术,对它的¹H、¹³C-NMR谱进行归属,进一步明确了它的结构。     

α-溴代丙烯酰胺衍生物与丙氨酸反应产物的结构鉴定

本文测定了α-溴代丙烯酰胺与丙氨酸反应产物的¹H,¹³C-NMR谱,采用NMR的各种技术对其谱线进行归属,鉴定出该产物的化学结构,是氮丙啶化合物的一对等量的非对映异构体的混合物,并讨论了¹H,¹³C-NMR谱与立体化学的关联。本文测定的氮丙啶化合物的非对映异构体的¹³CNMR谱未见报道。     

赤霉低酸及其衍生物的13C-NMR研究

用JMOD和DEPT技术,并结合氘标记和进行一些化学反应,确定了赤霉低酸及其一些衍生物的¹³C-NMR谱中的所有¹³C峰归属。     

水解聚丙烯酰胺的13C-NMR测定

本文研究了在不同pH条件下P(AM/AA)溶液的¹³C-NMR谱,观察了谱峰的化学位移变化和分裂情况,对比了均聚物PAM和PAA的¹³C-NMR谱,对P(AM/AA)¹³C-NMR谱的各共振峰进行了归属,证实P(AM/AA)共聚物C=O碳峰的分裂只与分子链共聚序列结构相关,并得出了C=O碳分裂峰所对应的三单元序列结构。     

九个苯并冠醚的13C-NMR谱研究

本文测定了九个苯并冠醚的¹³C-NMR和¹H-NMR谱,结合元素分析、红外、紫外、质谱等数据,确定了这些冠酸的分子结构。根据NMR谱的谱线位置、裂分情况及取代基诱导效应,归属了全部¹³C-NMR谱线。并讨论了苯环上不同取代基对冠醚环上各碳化学位移的影响。     

氢化丁苯共聚物结构的核磁共振波谱表征Ⅰ.13C谱带的归属

本文分别用JEOL FX-90Q和Bruker AM-300波谱仪测定了氢化聚丁二烯和氢化丁苯共聚物的¹H,¹³C-NMR谱,得到了分辨率较高的谱图和新的结构信息。借助DEPT技术确定了各谱带的CH或CH₂类型。利用Grant-Paul和Lindeman-Adams介绍的化学位移经验计算公式,考虑苯基对α、β和γ碳原子的影响,计算了各种三单元序列中有关碳原子的化学位移。对脂肪碳部分的28组谱带重新进行了归属。化学位移计算值与实测值基本相符,并得到了不同组成的模型聚合物¹³C-NMR谱的各谱带强度变化规律的验证。     

氢化丁苯共聚物结构的核磁共振波谱表征Ⅱ.微观结构的定量计算

在氢化丁苯共聚物¹³C-NMR谱脂肪碳部分谱带归属的基础上,根据各谱带的主要来源,推导出六个二单元浓度的计算公式。计算出二单元、一单元的相对含量,各结构单元的数均序列长度、嵌段含量和其它结构参数。加氢前后的¹H-和¹³C-NMR谱的组成计算结果基本一致。初步探讨了作为粘度指数改进剂的氢化丁苯共聚物微观结构与性能的关系,为合成提供了依据。     

含次环己基有机硅单体及二聚体的NMR谱与结构

含次环已基有机硅单体及其二聚体业已成功地合成^[1],本文研究了这类新单体和二聚体的¹H-NMR、¹³C-NMR、和²⁹Si-NMR谱,从而确定了它们的结构。     

云南甘草中齐墩果烷型五环三萜化合物的NMR谱的研究

本文研究了云南甘草皂甙元(glyyunnansapogenin)等oleanane类化合物的核磁共振谱。运用PBB,INEPT,DEPT方法,并结合化学位移值规律归属了这些化合物的¹³C-NMR信号。总结出用角甲基的化学位移植范围判定角甲基的取代位置的方法,分析了角甲基被氧取代后对环的化学位移值的影响。按类似olean-12-en,18α-H方式考虑,归属了oleana-11,13(18)-diene化合物的¹³C-NMR信号。讨论了具30→18β内酯或2929→18α内酯类化合物的核磁谱规律。另外,还发现了DE环上有1个OAC取代时,与其偕碳质子的化学位移值规律。     

Energy Level Statistics in Particle—Rotor Model

Energy level statistics of a system consisting of six particles interacting by delta force in a two-j model coupled with a deformed core is studied in particle-rotor model.For single-j shell (i13/2) and two-j shell (g7/2 d5/2) the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian,whilt in two-j case (i13/2 g9/2) the configuration truncation is used.The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin.The results of single-j shell are compared with those in two-j case.It is showed that the system becomes more regular when single-j space (i13/2) is replaced by two-j shell (g7/2 d5/2) although the basis size of the configuration space is unchanged.The degree of chaoticity of the system,however,changes slightly when configuration space is enlarged by extending single-j shell (i13/2) to two-j shell (i13/2 g9/2).     

几种叔丁墓酚化合物的核磁共振研究

研究了11种叔丁基酚化合物的化学位移和偶合常数,并讨论了影响因素.     

德拉沙星葡甲胺波谱学数据解析

本文采用元素分析、紫外吸收光谱、红外吸收光谱、质谱和核磁共振（NMR）波谱（包含¹H NMR、¹³C NMR、DEPT、¹H-¹H COSY、¹H-¹³C HSQC和¹H-¹³C HMBC）等方法对德拉沙星葡甲胺进行了结构分析,确证了德拉沙星葡甲胺的结构,分析了其IR谱图特征吸收峰对应的基团,对其¹H和¹³C NMR信号进行了完整归属.并通过差示扫描量热法、热重分析及粉末X-射线衍射分析对德拉沙星葡甲胺的晶型进行了初步研究.     

Rapid solid-state NMR of deuterated proteins by interleaved cross-polarization from ¹H and ²H nuclei

We present a novel sampling strategy, interleaving acquisition of multiple NMR spectra by exploiting initial polarization subsequently from (1)H and (2)H spins, taking advantage of their different T(1) relaxation times. Different (1)H- and (2)H-polarization based spectra are in this way simultaneously recorded improving either information content or sensitivity by adding spectra. The so-called Relaxation-optimized Acquisition of Proton Interleaved with Deuterium (RAPID) (1)H→(13)C/(2)H→(13)C CP/MAS multiple-acquisition method is demonstrated by 1D and 2D experiments using a uniformly (2)H, (15)N,(13)C-labeled α-spectrin SH3 domain sample with all or 30% back-exchanged labile (2)H to (1)H. It is demonstrated how 1D (13)C CP/MAS or 2D (13)C-(13)C correlation spectra initialized with polarization from either (1)H or (2)H may be recorded simultaneously with flexibility to be added or used individually for spectral editing. It is also shown how 2D (13)C-(13)C correlation spectra may be recorded interleaved with (2)H-(13)C correlation spectra to obtain (13)C-(13)C correlations along with information about dynamics from (2)H sideband patterns.     

二维相关荧光光谱探究土壤富里酸亚组分的质子键合多相性

利用同步荧光光谱（SFS）结合二维相关光谱（2D COS）和修正Stern-Volmer模型探究了森林土壤富里酸（FA）亚组分的质子键合多相性。利用XAD-8吸附树脂结合Na₄P₂O₇缓冲溶液逐步洗脱方法成功将土壤FA分级为异质性低的FA亚组分（FA₃-FA₁₃）。FA₃-FA₁₃含有类蛋白（类酪氨酸和类色氨酸）、类富里酸和类腐殖酸组分，且FA₇-FA₁₃比FA₃和FA₅含有更多含量的类蛋白组分。FA₃-FA₁₃中不同荧光组分的光谱峰强受溶液碱性pH值变化的影响较为明显。FA₃-FA₁₃的2D COS同步和异步相关谱图中自峰和交叉峰的复杂分布与荧光组分的质子键合多相性有关。FA₅-FA₁₃中类蛋白、类富里酸和类腐殖酸组分因pH值变量扰动而产生的光谱变化方向相同。在碱性pH值条件下，修正Stern-Volmer模型定量拟合FA₃-FA₁₃中荧光组分的解离常数（pK_a值），其中类酪氨酸、类色氨酸、类富里酸和类腐殖酸的pK_a值范围分别为6.11，8.93～10.12，9.32～10.65和9.70～10.63（R>0.854）。FA₃中类酪氨酸组分的低pK_a值（6.11）表明类酪氨酸组分含有更多含量的芳香族结构和相邻酚基官能团。FA₃-FA₁₃中类色氨酸、类富里酸和类腐殖酸组分的相似pK_a值（8.93～10.65）与羟基苯和氨基酸的pK_a值（8.0～12.02）相近，表明类色氨酸、类富里酸和类腐殖酸组分具有相似的质子亲和力，且酚基官能团和氨基酸组分在其质子键合过程中起主要作用。FA₃-FA₁₃中特定波长处荧光组分的波长连续变化顺序与其pK_a值递增趋势相一致，且质子结合位点的多相性特征同时存在于FA亚组分的不同荧光组分间和相同荧光组分内。FA₃中特定波长处类酪氨酸和类色氨酸组分的pK_a值（6.11～9.16）小于类腐殖酸组分（9.70～9.97），且荧光组分的递增趋势与波长连续变化的顺序（250 nm→275 nm→425～490 nm）相一致。FA₅-FA₁₃中特定波长处类色氨酸组分、类富里酸和类腐殖酸组分的pK_a值递增趋势与波长连续变化的顺序表现出相一致的规律：275 nm（8.93～9.70）→375～495 nm（9.88～10.16）→350 nm（10.65）（FA₅和FA₇），275 nm（10.11）→290～400 nm（10.35）（FA₉）和265～345 nm（9.32～9.80）→360～450 nm（10.06～10.13）（FA₁₃）。同时，FA₁₃中同一类富里酸组分的波长和pK_a值存在325 nm（9.32）→375～425 nm（10.06～10.13）的连续变化顺序。SFS-2D COS结合修正Stern-Volmer模型具有降低光谱重叠率和捕获光谱波长连续变化的优势，为深入研究有机质和污染物间复杂相互作用提供支撑。     

13C and 15N distributions in three spodic dystric cambisols under beech and spruce

The study of natural isotopic abundance signatures is useful to gain further insights in the processes resulting in depthwise changes in the composition of soil organic matter (SOM). Objectives were to describe the delta 13C and delta 15N abundances of SOM with depth in soils from a 153-year old beech (B1), a 119-year old spruce (F1) and a 61-year old spruce (F2) stand at Solling, north-west Germany, and to study, how podzolisation affects the isotopic abundances of 13C and 15N in the SOM. The degree of podzolisation decreased in the order F1 > B1 > F2. At the surface of the humus layer of all three sites, delta 13C values are approximately 1 to 4/1000 higher than in the leaves and needles, probably mainly due to the discrimination of 13C by microbial decomposition. 13C abundances in the organic layers of B1 and F2 increased only slightly from -27.6/1000 PDB (B1, L) to -27.2/1000 PDB (B1, Oh) and from -26.3/1000 PDB (F2, L) to -25.9/1000 PDB (F2, Oh), suggesting that biotic activity resulted in mixing of organic matter. At F1, however, 13C abundance increased from -27.5/1000 PDB (L) to -26.0/1000 PDB (Oh) which reflects the lack of mixing by animals. In the upper 2-4 cm of the mineral soil, i.e., in the eluvial horizons Aeh, 13C values showed a minimum at the spruce sites which was presumably related to a translocation of 13C enriched fulvic acids. Depthwise changes in delta 15N values were not related to podzolisation processes. At all three sites, a 13N enrichment with depth occurred in the mineral soil which is the result of the discrimination of 15N by microbial decomposition.     

The electrical properties and phase transformation of PLZST 2/85/13/2 antiferroelectric thin films on different bottom electrode

Pb_0.97La_0.02(Zr_0.85Sn_0.13Ti_0.02)O₃ (PLZST 2/85/13/2) antiferroelectric thin films were deposited on Pt(111)/Ti/SiO₂/Si and LaNiO₃(LNO)/SiO₂/Si substrates through a modified sol-gel process. The phase structure and microstructure of PLZST 2/85/13/2 antiferroelectric thin films were analysed by x-ray diffraction (XRD), scanning electron microcopy (SEM) and field-emission SEM (FE-SEM). The antiferroelectric nature of the PLZST 2/85/13/2 thin films on two electrodes was demonstrated by the C-V (capacitance-voltage) and P-E (polarization-electric field) measurement. The maximum polarizations for PLZST 2/85/13/2 films on Pt and LNO electrodes were 42 and 18 μC/cm², respectively. The temperature dependence of the dielectric property of the PLZST 2/85/13/2 films was measured under different dc electric fields. Also, the phase transformation of the PLZST 2/85/13/2 films was studied in detail as a function of temperature and dc electric field.     

取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构——7.氢化丁苯共聚物(HBS)

测定了两个氢化丁苯共聚物样品的¹H、¹³C NMR谱。通过处理文献中的¹³C NMR谱数据得到了-C₂H₅和-C₆H₅的SCS参数。利用乙烯-α-烯烃共聚物的SCS方法结合DEPT NMR实验技术重新归属了该共聚物的¹³C NMR谱。明确指出,氢化丁苯共聚物分子链中主链任何一个乙烯单元的两个CH₂在序列分布上分属于二元组和三元组。CH则用三元组来表征。最后,对HBS共聚物的序列分布进行了计算。     

1,2-二氢-4-苯基(2H)二氮杂萘酮的NMR谱研究

报道了1,2-二氢-2-(4-氨基苯基)-4-[4-(4-氨基苯氧基)苯基](2H)二氮杂萘-1-酮的合成,并用2D同核化学位移相关谱(¹H,¹H-COSY),2DROESY谱,2D异核¹³C-¹H相关谱和2D异核¹³C-¹H多键相关谱(HMBC)对该化合物的¹H和¹³C NMR谱进行了完整归属,证明了此化合物是含二氮杂萘酮结构,而不是二氮杂萘醚结构.     

抑制HMQC实验中与碳-12相连质子的信号

建议了一个新的HMQC实验的脉冲序列,其准备期和混合期分别为90°_x(¹H)-τ/2-180°^x(¹H,¹³C)-τ/2-90°_x(¹H,¹³C)和90°_x(¹³C)-τ/2-180°_x(¹H,¹³C)-τ/2-,以及τ=(2J_CH)^-1(J_CH为C-H偶合常数).在这个新的HMQC实验中,与碳-12相连质子的信号被有效地抑制,其抑制的机理与脉冲的相位循环无关.从而,它可以用于有效地抑制HMQC谱的噪音.特别是,在没有脉冲梯度场装置时,该方法显得非常实用