Low temperature FTIR, Raman, NMR spectroscopic and theoretical study of hydroxyethylammonium picrate

A combined experimental (infrared, Raman and NMR) and theoretical quantum chemical study is performed on the charge-transfer complex hydroxyethylammonium picrate (HEAP). The infrared (IR) spectra for HEAP were recorded at various temperatures, ranging from 16 K to 299 K, and the Raman spectrum was recorded at room temperature. A comparison of the experimental IR and Raman spectra with the corresponding calculated spectra was done, in order to facilitate interpretation of the experimental data. Formation of the HEAP complex is evidenced by the presence of the most prominent characteristic bands of the constituting groups of the charge-transfer complex e.g., NH3+, CO- and NO2]. Vibrational spectroscopic analysis, together with natural bond orbital (NBO) and theoretical charge density analysis in the crystalline phase, was used to shed light on relevant structural details of HEAP resulting from deprotonation of picric acid followed by formation of a hydrogen bond of the N-H center dot center dot center dot OC type between the hydroxyethylammonium cation and the picrate.C-13 and H-1 NMR spectroscopic analysis are also presented for the DMSO-d(6) solution of the compound revealing that in that medium the HEAP crystal dissolves forming the free picrate and hydroxyethylammonium ions. Finally, the electron excitation analysis of HEAP was performed in an attempt to determine the nature of the most important excited states responsible for the NLO properties exhibited by the compound. (C) 2015 Elsevier B.V. All rights reserved.

Chemical Shifts to Metabolic Pathways: Identifying Metabolic Pathways Directly from a Single 2D NMR Spectrum

Identifying cellular processes in terms of metabolic pathways is one of the avowed goals of metabolomics studies. Currently, this is done after relevant metabolites are identified to allow their mapping onto specific pathways. This task is daunting due to the complex nature of cellular processes and the difficulty in establishing the identity of individual metabolites. We propose here a new method: ChemSMP (Chemical Shifts to Metabolic Pathways), which facilitates rapid analysis by identifying the active metabolic pathways directly from chemical shifts obtained from a single two-dimensional (2D) C-13-H-1] correlation NMR spectrum without the need for identification and assignment of individual metabolites. ChemSMP uses a novel indexing and scoring system comprised of a ``uniqueness score'' and a ``coverage score''. Our method is demonstrated on metabolic pathways data from the Small Molecule Pathway Database (SMPDB) and chemical shifts from the Human Metabolome Database (HMDB). Benchmarks show that ChemSMP has a positive prediction rate of >90% in the presence of deduttered data and can sustain the same at 60-70% even in the presence of noise, such as deletions of peaks and chemical shift deviations. The method tested on NMR data acquired for a mixture of 20 amino acids shows a success rate of 93% in correct recovery of pathways. When used on data obtained from the cell lysate of an unexplored oncogenic cell line, it revealed active metabolic pathways responsible for regulating energy homeostasis of cancer cells. Our unique tool is thus expected to significantly enhance analysis of NMIR-based metabolomics data by reducing existing impediments.

含有C，H，O有机化合物结构解析专家系统的研究

本文系统地介绍了一个有机化合物结构解析专家系统的研究过程，该系统包括约束知识库，整体结构产生器，和结构验证器三个部分。本工作侧重两个部分，即约束规则的生成和整体结构对接。所涉及的章节为第六——十章。第一——五章为本论文的文献综述部分。第六章介绍了结构解析专家系统的总体设计及理论依据，我们的专家系统的总体设计是：由分子式或光谱数据出发，推导出与未知化合物的分子式和光谱数据相一致的结构片断。应用离散数学，布尔代数，图论，数理逻辑，拓扑学，组合数学等各种理论手段，将结构片断穷举生成整体结构，即候选化合物。最后应用模式识别，波谱模拟，涨力能计算等方法进行结构验证，自动排除与各种约束条件不一致的候选化合物，以求得该未知化合物的最终结构。在理想的情况下，最终结构应是唯一的。对于复杂的化合物，系统可能给出一组最终结构。结构输出采用Carhart方案，即以化合物结构的二维联接表为基础，首先生成三维空间的一个构象，之后再投影到二维平面上。第七章是利用~（13）C-NMR波谱信息以产生结构生成的约束规则。具体方法是利用我们已建立的CIAC-~（13）C-NMR数据库系统进行~（13）-NMR化学位移与带有键属性的子结构相关研究。首先根据文献选出化合物中常见的子结构，进行数据库检索并统计出有关的化学位移。建立子结构与~（13）C-NMR化学位移相关表，当进行未知化合物的结构解析时，应用上述相关表寻找出未知化合物中的子结构约束条件。为了确保知识库的全面性以及结构生成的穷举性，第八章介绍一个子结构自动生成算法。其算法的思路是：首先选出常见元素的所有的基本结构基元，依次以每个结构基元为中心，然后考虑它与所有选定的结构基元联接情况。上述两种方案所得的相关表中的子结构是含有多种杂原子的，录O，N，S，P及卤素等。第九章介绍一个整体结构生成的算法及原理和程序设计思想。整体结构生成的过程是：首先生成一级亚结构向量，然后生成二级亚结构向量，再生成三级亚结构向量，由三级结构碎片进行对接，得到整体结构。目前该系统仅可对接含有C，H，O的化合物。第十章给出两个结构解析示例。

稀土配合物的NMR性质及在生物体系中应用的研究

本文从几个方面研究了稀土离子及稀土配合物的性质和在生物体系中的应用，并取得了如下结果。1)稀土离子具有良好的核磁特性。向外消旋丙－丝二肽溶液中加入顺磁性稀土离子，可使不同旋光异构体相同磁核的共振信号明显分开，便于指认和归属。指出外消旋丙－丝二肽顺磁稀土配合物不同异构体的诱导位移主要由接触位移决定；2)合成了几类Dy~(3+)配合物，并对其~(23)Na位移性质加以研究；3)稀土配合物Gd(DCBDA)、Gd(DBDA)、Gd(EDTMP)、Gd(DETPMP)、Gd_2(EDTMP)、Gd_2(DETPMP)具有很强的~(13)C弛豫增强作用，并不对~(13)C共振信号产生明显位移和增宽。Gd(DCBDA)、Gd(DBDA)弛豫能力最强，是很有应用前景的新型水溶性弛豫试剂；4)首次利用~(133)Cs NMR技术研究了稀土离子La~(3+)对人血红细胞金属离子迁移性质的影响。

Multi-electron processes in 4.15-11.08 keV/u(13)C(6+) on argon collisions

The relative partial cross sections for C-13(6+)-Ar collisions at 4.15-11.08 keV/u incident energy are measured. The cross-section ratios sigma(2E)/sigma(SC), sigma(3E)/sigma(SC), sigma(4E)/sigma(SC) and sigma(5E)/sigma(SC) are approximately the constants of 0.51 +/- 0.05, 0.20 +/- 0.03, 0.06 +/- 0.03 and 0.02 +/- 0.01 in this region. The significance of the multi-electron process in highly charged ions (HCIs) with argon collisions is demonstrated (sigma(ME)/sigma(SC) as high as 0.79 +/- 0.06). In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model (MCBM), the extended classical over-the-barrier (ECBM) and the semiempirical scaling laws (SL). The result is compared with these classical models and with our previous work of C-13(6+)-Ne collisions

醛酮类化合物的~(13)C核磁共振波谱模拟

为饱和醛酮类化合物的1 3C核磁共振波谱模拟 .根据该类化合物的特点 ,提取了分子的拓扑特征 ,几何特征及电子特征 .应用变量最优子集回归法进行了变量的选择 ,并用这些变量构造了回归模型 .交叉验证的结果表明 ,所得数学模型比较稳定 ,并得到了较好的预测结果

High resolution solid-state NMR and DSC study of poly(ethylene glycol) silicate hybrid materials via sol-gel process

Hybrid materials incorporating poly(ethylene glycol) (PEG) with tetraethoxysilane (TEOS) via a sol-gel process were studied for a wide range of compositions of PEG by DSC and high resolution solid-state C-13- and Si-29-NMR spectroscopy. The results indicate that the microstructure of the hybrid materials and the crystallization behavior of PEG in hybrids strongly depend on the relative content of PEG. With an increasing content of PEG, the microstructure of hybrid materials changes a lot, from intimate mixing to macrophase separation. It is found that the glass transition temperatures (T-g) (around 373 K) of PEG homogeneously embedded in a silica network are much higher than that (about 223 K) of pure PEG and also much higher in melting temperatures T-m (around 323 K) than PEG crystallites in heterogeneous hybrids. Meanwhile, the lower the PEG content, the more perfect the silica network, and the higher the T-g of PEG embedded in hybrids. An extended-chain structure of PEG was supposed to be responsible for the unusually high T-g of PEG. Homogeneous PEG-TEOS hybrids on a molecular level can be obtained provided that the PEG. content in the hybrids is less than 30% by weight. (C) 1998 John Wiley & Sons, Inc.

The structure analysis and characterization of N-100 by NMR

To improve the mechanics properties of polyurethane materials at a high or low temperature, a hydroxy compound N-100 of HDI was synthesized, The structure analysis and characterization were made by NMR (H-1, C-13, H-1-H-1 COSY, C-13-H-1 COSY), In addition, quantitative description of the network was made on the basis of some ideal assumptions, 1D and 2D NMR can differentiate four sorts of carbonyl groups and establish the connections of all carbon and hydrogen atoms of mixed structures that originated from five different substitutions, Besides, the alkene and isocyanate, urea, biuret and trimerized isocyanuric groups were also detected, Therefore, the structure of N-100 was suggested be a polyisocyanate with complicated network which contained nitrogen atom as cross-linkage, isocyanate and alkene as end groups, The consistence of calculated values with tested values of isocyanate content, mean function degree and mean molecular weight demonstrated the correct of structure characterization and the validity of network description.

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

NMR-STUDIES ON THE COORDINATION OF RARE-EARTHS WITH GLYCYL-DL-VALINE AND THE CONFORMATION OF THEIR COMPLEX IN AQUEOUS-SOLUTION

In this paper lanthanide-induced shifts have been measured for C-13 and H-1 nuclei of glycyl-DL-valine in the presence of three lanthanide cations (La3+, Ho3+ and Yb3+) in aqueous solution. The stability constants of the coordination compounds of rare earths (Ho, Yb) with glycyl-DL-valine have been calculated. The coordination of rare earths with the ligand has been discussed. The simulation for conformation of lanthanide coordination compounds with glycyl-DL-valine shows that the ligand is coordinated to lanthanide ion through oxygen atoms of carboxyl group and the bond length of Ln-O is 0.226 nm. In the coordination compounds glycyl-DL-valine is in extended state with minimal steric hindrance.

青藏高原东部高寒草甸植物δ~(13)C年间变化及其环境分析

植物有机体稳定碳同位素组成受植物生长期间气候环境因子的影响,包含了大量的环境信息。要真正理解植物体同位素组成所包含的环境信息首先要研究植物体同位素组成与环境之间的关系。文章通过分析2002年和2003年青藏高原东部青海省门源县境内隶属于19科41属51种植物叶片的δ~(13)C值,研究高寒草甸植物稳定碳同位素组成的年间变化及其与环境因子的关系,分析影响δ~(13)C值变化的关键因子。结果表明,所测植物的δ~(13)C值分布在一个很小的范围-29.2‰～-24.9‰之间,平均值为-26.9‰,说明所测植物的光合作用均通过C3途径实现,这可能与该研究区较低温度有关。研究发现一年生植物δ~(13)C值明显低于多年生植物,而且一年生和多年生植物δ~(13)C值之间的差异在2002年（t=-3.031,P〈0.01）和2003年（t=-3.567,P〈0.001）均能达到显著性水平,表明多年生植物水分利用效率显著高于一年生植物,能更好的适应该地区寒冷干燥的低温环境。两年间植物δ~(13)C值有明显不同,2003年显著低于2002年（t=6.786,P〈0.001）。通过分析两年间环境因子的变化认为植物叶片δ~(13)C值的年间变化主要是由于降水的变化引起的,随降雨量的增加而降低。不同植物种δ~(13)C值年间变化差别很大,反应了植物对环境变化的不同响应。在植被恢复中应选用植物δ~(13)C值随环境变化存在较大差异的物种,因为此类物种能够采取不同的对策适应该地区环境的变化。

吉林金川西大甸子泥炭沉积中火山物质的发现及其意义附：泥炭中胡敏酸的稳定碳同位素值（δ<'13>C）作为古气候代用指标可行性研究

泥炭以发育广泛、连续沉积好、沉积速率大（可达1mm/a甚至更大）、记录丰富等特点,正成为过去全球变化研究的良好综合地质档案.参考冰芯、黄土、深海沉积物等中矿物固体的研究思路和方法,希望能对泥炭中可能存在的火山物质和其它风粉尘进行研究.在对吉林金川西大甸子泥炭样品的处理过程中,摸索出一套泥炭样品中固体物质（如火山物质）初步的处理、分析方法;并对金川西大甸子干玛珥泥炭沉积中部一段泥砂状物质进行鉴定,首次发现火山玻璃,判断这些泥砂物为火山灰砂.目前研究表明,泥炭纤维素的δ<'13>C序列能较好地反映古气候变化,那么泥炭中胡敏酸的δ<'13>C序列可否也能反映古气候变化,该文对此作了初步研究.用碱溶酸沉淀方法从泥炭中提取出所谓的胡敏酸,用燃烧法将胡敏酸、纤维素中的碳转化为CO<,2>气体,测定它们的稳定碳同位素组成（δ<'13>C）.与能较好地反映气候变化的纤维素δ<'13>C序列相比,胡敏酸的δ<'13>C序列反映气候变化不明显.

N-H...S=C hydrogen bond in O-alkyl N-methoxycarbonyl thiocarbamates, ROC(S)N(H)C(O)O)CH(3) (R = CH(3)(-), CH(3)CH(2)-)

Pure O-methyl N-methoxycarbonyl thiocarbamate CH(3)OC(S)N(H)C(O)OCH(3) (I) and O-ethyl N-methoxycarbonyl thiocarbamate, CH(3)CH(2)OC(S)N(H)C(O)OCH(3) (II), are quantitatively prepared by the addition reaction between the CH(3)OC(O)NCS and the corresponding alcohols. The compounds are characterized by multinuclear ((1)H and (13)C) and bi-dimensional ((13)C HSQC) NMR, GC-MS and FTIR spectroscopy techniques. Structural and conformational properties are analyzed using a combined approach involving crystallographic data, vibration spectra and theoretical calculations. The low-temperature (150 K) crystal structure of II was determined by X-ray diffraction methods. The substance crystallizes in the monoclinic space group P2(1)/n with a = 4.088(1)angstrom. b = 22.346(1)angstrom, c = 8.284(1)angstrom, beta = 100.687(3)degrees and Z = 4 molecules per unit cell. The conformation adopted by the thiocarbamate group -OC(S)N(H)- is syn (C=S double bond in synperiplanar orientation with respect to the N-H single bond), while the methoxycarbonyl C=O double bond is in antiperiplanar orientation with respect to the N-H bond. The non-H atoms in II are essentially coplanar and the molecules are arranged in the crystal lattice as centro-symmetric dimeric units held by N-H center dot center dot center dot S=C hydrogen bonds Id(N center dot center dot center dot S) = 3.387(1)angstrom, <(N-H center dot center dot center dot S) = 166.4(2)degrees]. Furthermore, the effect of the it electronic resonance in the structural and vibrational properties is also discussed. (C) 2009 Elsevier Ltd. All rights reserved.

Antitumor and antimycobacterial activities of cyclopalladated complexes: X-ray structure of [Pd(C-2,N-dmba)(Br)(tu)] (dmba = N,N-dimethylbenzylamine, tu = thiourea)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

NMR study of styrene-butadiene rubber (SBR) and TiO2 nanocomposites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)