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1.
测得并解析了2个蝶状铁硒取代衍生物(μ-p-MeC6H4Se)2Fe2(CO)2(Ph2PCH2CH2PPh2)(A)和(μ-p-MeC6H4Se)2Fe2(CO)4(cis-Ph2PCH=CHPPH2)(B)的^1H-^1HCOSY谱和^1H-^15CCOSY谱以及A的^1H-^1HNOESR谱,从而进一不确证了它们的结构。  相似文献   

2.
景凤英  姜洪焱 《分析化学》1998,26(4):461-465
利用一维NMR方法研究了新型聚芳醚酮大环化合物的影响,用二维同核^1H-^1H COSY和^13C-^1H COSY实验方法以及类似物质标准谱图的比较,对一维NMR谱峰进行了归属。  相似文献   

3.
本文以UV、FTIR、^1H-NMR、^13C-NMR、FABMS等现代分析手段,对国内试制的新型胃动力药盐酸伊托必利的化学结构进行了分析鉴定。根据谱带与结构的对应关系,确证其结构与国外已报道的结构一致并对上述各种谱的谱带进行了全面的归属  相似文献   

4.
于鹏  景晓燕 《分析化学》1999,27(11):1337-1340
用^1H NMR和^13C NMR谱研究了新型电化学发光探针六氟磷酸二(4,4’;-二甲基-2,2‘-联吡啶).(4.4’-二羧酸-2,2‘-联吡啶)合钌的立体结构,通过^1H ^1H COSY,^13C-^1H HETCOR谱对其氢谱和碳谱中的各谱峰进行了归属,并给出了氢谱和碳谱峰的化学位移值。  相似文献   

5.
SYNTHESIS,CHARACTERIZATIONOF2-[2-(3-NITRO-4-METHOXYLPHENYL)VINYLI-1-METHYLPYRIDINIUMPENTAANDHEXANITRATORAREEARTH(Ⅲ)COMPLEXESH...  相似文献   

6.
用一维^H NMR、^13C NMR方法研究了对甲氧基偶氮苯衍生物的结构,并通过二维^1H-^1H同核相关谱(COSY)、^13C-^1H异核相关谱(HETCOR)及^13C-^1H异核远程相关谱进一步地确定了该类衍生物的^1H和^13C谱中各谱峰的归属,为研究侧链液晶聚合物结构提供了有价值的数据。  相似文献   

7.
具有抗HIV病毒活性的杂多酸HPA-23与谷胱甘肽的作用   总被引:2,自引:0,他引:2       下载免费PDF全文
以谷胱甘肽作为病毒包络蛋白的模拟物,用NMR方法研究了与具有抗爱滋病病毒活性杂多酸HPA-23的作用。对不同配比的HPA-23和谷胱甘肽混合物的^1H和^1^8^3WNMR谱研究结果表明,还原型和氧化型谷胱甘肽均以C末端COO^-与HPA-23骨架的钨原子配位,还原型谷胱甘肽侧链上的巯基(SH)也参加配位。COSY谱证明了SH配位为慢交换反应。早在七十年代初,人们就发现杂多酸具有抗病毒活性。最近报  相似文献   

8.
FLUORESCENCE STUDIES ON SELF-ASSEMBLING BEHAVIOR OF AMPHIPHILES WITH NAPHALENE-1,5-DIOXY GROUPFLUORESCENCESTUDIESONSELF-ASSEM...  相似文献   

9.
用一维NMR方法研究了新型电化学发光探针Ru(dcbpy)(phen)2(PF6)2的立体结构,借助二维^1H-^1H COSY和^1H-^13C COSY实验对其氢谱和碳谱进行了完全的归属,并给出了其氢谱和碳谱的化学位移值。  相似文献   

10.
用^1H-NMR^13C-NMR和二维核共振技术研究了2,2’-二(对氨苯氧基)-1,1’-联萘的结构,并通过^1H-^1H质子同核相关及^13C-^1H异核相关谱提供的信息确定了其^1H谱和^13C谱中各谱峰的归属,为聚合物的表征提供依据。  相似文献   

11.
A new 1H DQ (double-quantum) CRAMPS (combined rotation and multiple-pulse sequence) solid-state nuclear magnetic resonance experiment incorporating DUMBO homonuclear 1H dipolar decoupling is presented. The major resolution enhancement enables DQ peaks corresponding to all 22 close (<3.5 A) proton-proton proximities in the dipeptide beta-AspAla to be observed. In particular, the DQ CRAMPS spectrum provides access to the alkyl region of the spectrum and yields a clear assignment of the two CH and two diastereotopic CH2 proton resonances.  相似文献   

12.
In order to shed light on the proton distributions and order/disorder in high-pressure delta-Al(OH)3 and delta-AlOOH phases, two-dimensional, high-resolution 1H CRAMPS (FSLG)-MAS NMR and 27Al 3QMAS NMR spectra have been obtained. For delta-Al(OH)3, the 1H CRAMPS-MAS NMR revealed two peaks with an intensity ratio close to 2:1. The 27Al MAS and 3QMAS NMR suggest a single Al site with a well-defined local structure. For delta-AlOOH, the 1H and 27Al NMR indicate the presence of a single H and Al site each. These results are consistent with crystal structures refined from X-ray diffraction. For comparison, 1H MAS and CRAMPS-MAS NMR spectra were also obtained for several other hydroxides/oxyhydroxides, including In(OH)3 and InOOH that have similar structures to delta-Al(OH)3 and delta-AlOOH, respectively. These data not only provide additional insights into the proton distributions in these important crystal structure classes but also together provide a better defined quantitative correlation between 1H chemical shift and hydrogen-bonding O...O distance.  相似文献   

13.
High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.  相似文献   

14.
The montmorillonite samples from Heping, China had been studied by chemical analysis, DAT, TG, XRD and MAS NMR. The results showed that the hydroxyl in octahedra sheets begins dehydrating, when the thermal treatment temperature reaches 650 degrees C, but the layer structure remains, the corresponding Al(VI) was turned into Al(IV) in octahedra sheets. When the temperature reaches 900 degrees C, the layer structure of montmorillonite is destroyed, and the new mineral phase mu-cordierite is found. When the temperature reaches 1200 degrees C, the mu-cordierite phase loses stability, and decomposes into cristobalite phase and mullite phase, meanwhile, the recrystallization phenomena in thermal treatment products is obvious. There is a small quantity of Al(VI) signal in MAS NMR spectrum, this Al(VI) corresponds to the Al of mullite. When the temperature reaches 1350 degrees C, the cristobalite and mullite phases reduce slightly, and more Fe-cordierite phase appear. There is corresponding Fe-cordierite spectrum in XRD and MAS NMR.  相似文献   

15.
液晶型聚氨酯弹性体的固体高分辨核磁共振研究   总被引:1,自引:0,他引:1  
采用固体高分辨^13C核磁共振谱以及溶液碳谱、氢谱的方法对以聚四氢呋喃(PTMO)为软段、4,4'-二苯基甲烷二异氰酸酯(MDI)为硬段、4,4'-二羟已氧基联苯(HB6)为扩链剂的液晶型聚氨酯弹性体的相态结构、分子运动、氢键相互作用等问题进行了研究。探讨了样品的化学结构与上述问题间的关系。  相似文献   

16.
The structural change near the phase transition temperatures of [NH2(CH3)2]2CuCl4 is discussed in terms of the chemical shifts and the spin-lattice relaxation times T in the rotating frame for 1H MAS NMR and 13C CP/MAS NMR. The 1H T undergoes molecular motion near the phase-transition temperature (TC2 = 253 K). In addition, the two inequivalent [NH2(CH3)2] (1) and [NH2(CH3)2] (2) sites were distinguishable by the 13C chemical shift. And, the most significant change was observed at TC2 for the 13C CP/MAS NMR spectrum; this temperature corresponds to a ferroelastic phase transition with different orientations.  相似文献   

17.
分子间相互作用是决定材料结构和性能的关键因素之一,而如何在分子水上实现对复杂相互作用分子的检测仍然是一个挑战性课题。本工作首先在不同p H值条下以聚丙烯酸/聚环氧乙烷(PAA/PEO)的混合水溶液制备了系列的固体薄膜,然后采用多种基于连续相调制多脉冲技术的一维和二维~1H多脉冲去耦(CRAMPS)固体NMR新技术,并结合高分辨~(13)C交叉极化魔角旋转(CPMAS)、~(23)Na多量子(MQ)等多核固体NMR实验,对PAA/PEO聚合物共混物的微观结构和动力学进行了原位和系统的研究。通过不同类型的~1H高分辨CRAMPS实验检测到共混物中包含多种不同类型质子:通过氢键相互作用形成二聚体的COOH基团、自由COOH基团、与水结合的COOH基团和主链基团。随着p H值的升高,除主链质子外,大部分其它区域的信号都明显降低,这是由于PAA与PEO以及水的氢键作用减弱所致。这些CRAMPS NMR技术也被用来阐明不同p H值制备的样品中不同基团的分子运动性。此外,二维~1H-~1H自旋交换NMR实验提供了关于聚合物PAA与PEO大分子链间、以及水与聚合物的相互作用。~1H自旋扩散实验表明,在这些共混物中明显存在相微观相分离的结构,并且测定的分散相区尺寸约为17 nm。~(23)Na MQMAS实验揭示了在共混物中存在两种类型~(23)Na位,一种是自由的钠离子,另一种是与大分子相互作用的Na离子。特别是通过~1H-检测的~(23)Na-~1H CPMAS实验揭示了Na~+离子的位置远离PEO而与PAA临近。上述这些SSNMR实验结果在分子水平上提供了氢键相互作用对PAA/PEO共混物微观结构和动力学影响的详细信息,可以获得不同p H值对PAA与PEO的氢键作用、相容性、微观结构、水-聚合物相互作用和不同组分分子运动性的影响。在上述核磁共振研究的基础上,我们提出了一种新的PAA/PEO共混物的结构模型,该模型首次成功地揭示了不同的p H值对PAA/PEO共混物中微观结构和动力学的影响。本工作清楚地表明,固态核磁共振是在分子水平上研究具有复杂相互作用的多相聚合物材料的有力工具。本文的研究工作对于探索检测聚合物弱相互作用的新方法和发展基于氢键相互作用的聚合物新材料的开发具有重要意义。  相似文献   

18.
The complex hydrogen-bonding arrangement in the biologically important molecule bilirubin IXalpha is probed by using 1H double-quantum (DQ) magic-angle spinning (MAS) NMR spectroscopy. Employing fast MAS (30 kHz) and a high magnetic field (16.4 T), three low-field resonances corresponding to the different hydrogen-bonding protons are resolved in a 1H MAS NMR spectrum of bilirubin. These resonances are assigned on the basis of the proton-proton proximities identified from a two-dimensional rotor-synchronized 1H DQ MAS NMR spectrum. An analysis of 1H DQ MAS spinning-sideband patterns for the NH protons in bilirubin allows the quantitative determination of proton-proton distances and the geometry. The validity of this procedure is proven by simulated spectra for a model three-spin system, which show that the shortest distance can be determined to a very high degree of accuracy. The distance between the lactam and pyrrole NH protons in bilirubin is determined to be 0.186 +/- 0.002 nm (corresponding to a dominant dipolar coupling constant of 18.5 +/- 0.5 kHz). The analysis also yields a distance between the lactam NH and carboxylic acid OH protons of 0.230 +/- 0.008 nm (corresponding to a perturbing dipolar coupling constant of 9.9 +/- 1.0 kHz) and an H-H-H angle of 122 +/- 4 degrees. Finally, a comparison of 1H DQ MAS spinning-sideband patterns for bilirubin and its dimethyl ester reveals a significantly longer distance between the two NH protons in the latter case.  相似文献   

19.
Upon slow cooling, a small fraction of the thermotropic liquid crystal S1496 exhibits a new phase which shows a high-resolution carbon-13 NMR spectrum with isotropic chemical shifts. This new phase is probably either cubic phase or a plastic phase. Its formation is facilitated by the addition of small amounts of solutes. Some other liquid crystals containing alkylcyclohexanes behave similarly.  相似文献   

20.
A new aluminum fluoride, Al(2)F(8).2NC(5)H(6).C(6)H(3)(CO(2)H)(3), was synthesized under mild hydrothermal conditions (200 degrees C, 3 days) in the presence of 1,3,5-benzenetricarboxylic acid (btc) in pyridine/HF (pyr/HF) solvent. Its structure is characterized with single-crystal XRD analysis and high-resolution solid-state NMR. The inorganic framework consists of the corner- and edge-shared connections of AlF(6) octahedra. They are linked via a common edge and form a bioctahedral motif which is trans-connected through the corner-shared fluorine. It results in the formation of an original infinite double file of AlF(6) octahedra running along the a axis. A high-power decoupled MAS (27)Al{(19)F} Hahn echo NMR spectrum allowed us to distinguish the two crystallographic hexacoordinated Al sites. Four unresolved (19)F NMR signals are observed in the MAS spectra to account for the eight crystallographic fluorine atoms. Half of the terminal fluorine sites interact via strong hydrogen bonds with the ammonium groups of the pyridine moieties. The resulting mixed pyridine-fluoroaluminate chains are intercalated by the btc molecules which are hydrogen-bonded to the remaining free terminal fluoride anions through the protonated carboxylic acid function. The (1)H nuclei of both organic molecules are observed in the protonated form.  相似文献   

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