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1.
雪胆素C是一个雪胆素甲在碱性条件下,乙酰基转移产生的同分异构体. 文中报道了应用13C NMR-DEPT、1H-1H COSY, NOESY, 13C-1H COSY等多种NMR技术,对雪胆素C的NMR碳氢化学位移完全指定.  相似文献   

2.
用2D NMR技术研究了从银杏叶提取物中分离的一个黄酮双糖甙[槲皮素-3-鼠李糖-(6-对羟基反式桂皮酰)葡萄糖甙]的结构,对鼠李糖部分的1H NMR,13C NMR化学位移进行了归属.13C化学位移和1H NOE相关性都证明鼠李糖为1″-2″连接.  相似文献   

3.
用2D NMR (1H-1H COSY和1H-13C COSY)技术研究了从鹰瓜花中分离到的黄酮醇-3-O-吡喃鼠李糖基呋喃阿拉伯糖甙的双糖结构,明确其双糖为1→2连接.  相似文献   

4.
运用2D NMR技术,如DQF 1H-1H COSY,HMQC,HMBC,TOCSY等,对3 个原人参二醇型双糖链配糖体人参皂甙-Rd,三七皂甙-E和七叶胆皂甙XVII的氢和碳的化学位移首次进行了全归属.  相似文献   

5.
应用1D NMR和脉冲梯度场2D NMR技术深入研究盐酸托哌酮的溶液结构,对其1H和13C NMR化学位移进行全归属,并讨论其立体化学.  相似文献   

6.
王明安  吕冬 《波谱学杂志》1998,15(4):371-374
1H-1H COSY,13C-1H COSY,HMBC,NOESY,DEPT以及同核去偶技术,表征了芳香维甲酸乙酯的化学结构,对其1H NMR,13C NMR化学位移进行了指认.  相似文献   

7.
为研究中药射干(Belamcanda chinensis)的化学成分,应用多种柱色谱方法对其乙醇提取物进行分离和纯化,并得到了11个异黄酮化合物,通过1H NMR、13C NMR及HMBC、HSQC、1H-1H COSY、NOESY等波谱手段解析化学结构,发现一个新化合物,命名为异野鸢尾苷. 对这些化合物的1H NMR和13C NMR进行了完全归属,并探讨了取代基对1H、13C化学位移的影响.  相似文献   

8.
应用1D NMR 和梯度2D NMR技术(gCOSY,gNOESY,gHSQC,gHMBC)深入研究了从链霉菌发酵物中分离提取得到的Manumycin的结构,并对其1H和13C NMR化学位移进行了全归属. 计算机分子模拟与NMR研究取得一致结论.  相似文献   

9.
对叶百部烯酮和对叶百部酮的2D NMR研究   总被引:1,自引:0,他引:1  
从华北产对叶百部(Stemona tuberosa Tour)根部分离出两种生物碱,对叶百部烯酮1(tuberostemoenone)和对叶百部酮2(tuberostemonone),其中化合物1的结构未见报道.应用2D NMR梯度反相实验,GCOSY、GNOESY、GHMQC和GHMBC对其化学结构进行了深入研究,归属了其1H、13C NMR化学位移.计算机分子模拟与NMR研究取得一致结论.  相似文献   

10.
苯基哌嗪衍生物的NMR波谱研究   总被引:2,自引:0,他引:2  
通过1H NMR、13C NMR、及HMBC、HSQC、1H-1H DQFCOSY等2D NMR方法对新合成的10个苯基哌嗪衍生物类抗高血压药物进行结构鉴定, 并对这些化合物的1H NMR和13C NMR信号进行了全归属. 初步探讨了取代基对分子13C化学位移的影响.   相似文献   

11.
In this Communication, we demonstrate the use of deuteration together with back substitution of exchangeable protons as a means of attenuating the strong 1H-1H couplings that broaden 1H magic angle spinning (MAS) spectra of solids. The approach facilitates 15N-1H correlation experiments as well as experiments for the measurement of 1H-1H distances. The distance measurement relies on the excellent resolution in the 1H MAS spectrum and homonuclear double quantum recoupling techniques. The 1H-1H dipolar recoupling can be analyzed in an analytical fashion by fitting the data to a 2- or 3-spin system. The experiments are performed on a sample of the dipeptide N-Ac-Val-Leu-OH, which was synthesized from uniformly [2H, 15N] labeled materials and back-exchanged in H2O.  相似文献   

12.
A method for enhancing the sensitivity of 15N spectra of nonspinning solids through 1H indirect detection is introduced. By sampling the 1H signals in the windows of a pulsed spin-lock sequence, high-sensitivity 1H spectra can be obtained in two-dimensional (2D) spectra whose indirect dimension yields the 15N chemical shift pattern. By sacrificing the 1H chemical shift information, sensitivity gains of 1.8 to 2.5 for the 15N spectra were achieved experimentally. A similar sensitivity enhancement was also obtained for 2D (15)N-(1)H dipolar and 15N chemical shift correlation spectroscopy, by means of a 3D 1H/15N-1H/15N correlation experiment. We demonstrate this technique, termed PRINS for proton indirectly detected nitrogen static NMR, on a crystalline model compound with long 1H T(1rho) and on a 25-kDa protein with short 1H T(1rho). This 1H indirect detection approach should be useful for enhancing the sensitivity of 15N NMR of oriented membrane peptides. It can also be used to facilitate the empirical optimization of 15N-detected experiments where the inherent sensitivity of the sample is low.  相似文献   

13.
本文对KBr压片法、KCl压片法以及萨特勒图谱采用的,糊剂法所绘制的三氯异氰尿酸的红外光谱进行了分析、对照。KCl压片法克服了溶剂的影响,简单、直观地体现了物质的精细结构。同时,将三氯异氰尿酸分别与KCl、KBr研磨,和三氯异氰尿酸纯品进行了紫外-可见吸收光谱对照。实验发现,与KBr研磨的三氯异氰尿酸和纯品的吸收峰有差异,而与KCl研磨后的三氯异氰尿酸和纯品一致,说明结构未发生变化。因此,认为KCl压片法是绘制三氯异氰尿酸红外光谱较好的方法。  相似文献   

14.
磷掺杂纳米硅薄膜的研制   总被引:8,自引:0,他引:8       下载免费PDF全文
用PECVD薄膜沉积方法,成功地制备了磷掺杂纳米硅(nc-Si:H(P))薄膜.用扫描隧道电镜(STM)、Raman散射、傅里叶变换红外吸收(FTIR)谱、电子自旋共振(ESR)、共振核反应(RNR)技术对掺磷纳米硅进行了结构分析,确认了样品的微结构为纳米相结构.掺磷后膜中纳米晶粒的平均尺寸d减小,一般在25—45nm之间,且排列更加有序.掺磷nc-Si:H膜具有较高的光吸收系数,光学带隙在173—178eV之间,和本征nc-Si:H相同.掺杂nc-Si:H薄膜电导率在10-1关键词:  相似文献   

15.
Yang R  Guo X  Wang W  Zhang Y  Jia L 《Journal of fluorescence》2012,22(4):1065-1071
A new OFF-ON fluorescent chemosensor (H1) composed of a naphthalimide fluorophore and a 6-[(quinolin-8-yloxy)methyl]pyridin-2-ylmethanamine receptor has been synthesized and characterized by infra-red, (1)H NMR, (13)C NMR and mass spectrometry. The developed chemosensor H1 exhibited good turn-on and reversible responses toward Hg(2+), with excellent selectivity and sensitivity, in a neutral buffered aqueous solution. Other common metal ions did not interfere with the fluorescence-enhancement response to Hg(2+). Furthermore, the chemosensor H1, at a concentration of 10?μM, showed a rapid and linear response toward Hg(2+) in the concentration range 0-10?μM. On addition of 10?μM Hg(2+), the fluorescence intensity of H1 was enhanced about 4-fold. The detection limit was calculated to be 63?nM. The association constant was 1.11?×?10(5)?M(-1). The fluorescence quantum yield and lifetime of H1/Hg(2+) were 0.42 and 3.83?ns, respectively.  相似文献   

16.
张安将  黄枢 《波谱学杂志》1993,10(1):101-108
测定了3'(,3")-(二)甲酰基(二)苯并冠醚(1~7)的1H、13C谱,首次结合1H-1H COSY、13C-1H COSY、COLOC二维谱对这些化合物的1H、13C化学位移进行了归属。用NOESY谱确定了合成产物冠4、冠5的结构,并对溶液中的构象异构体及其溶剂影响进行了初探。作者以冠1~8的1H、13C谱的归属为参照,提出了正确归属冠醚醚环上次甲基1H、13C化学位移的一般规则。  相似文献   

17.
Journal of Applied Spectroscopy - The structure of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1H,3H)-dione (2) was proven using 13C, 1H, and 15N NMR spectroscopy. A new form (2a) was detected...  相似文献   

18.
黄向前  林陈昉  尹秀丽  赵汝光  王恩哥  胡宗海 《物理学报》2014,63(19):197301-197301
通过化学气相沉积法在一种典型的高指数面铜(410)-氧上制备出了一维石墨烯超晶格,并利用拉曼光谱(Raman)、低能电子衍射(LEED)、扫描隧道显微术(STM)等方法研究了氢原子在该超晶格上的吸附.实验结果揭示了由于超晶格的调制作用所引起的无缺陷石墨烯区域的选择性吸附,氢原子优先吸附在石墨烯超晶格一维周期中的相同部位.这一发现为进一步通过一维超晶格调控石墨烯的性质提供了更多可能.在石墨烯上的吸附氢原子除了单个或成对存在之外,实验还首次观察到一种新的三氢原子位型.  相似文献   

19.
To prove feasibility of proton chemical shift imaging ((1)H CSI) during stereotactic procedure, authors performed (1)H CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, evaluated the pathologic results. The (1)H CSI directed stereotactic biopsy was performed in four patients. (1)H CSI and conventional Gd-enhancement stereotactic MRI were performed simultaneously after the fitting of a stereotactic headframe. Focal areas of increased phosphocholine(Cho)/phosphocreatine(Cr) and Lactate/Cr ratios were selected as target sites in the stereotactic MR images. (1)H CSI is possible with the stereotactic headframe in place. Pathologic samples taken from areas of increased Cho/Cr ratios and decreased NAA/Cr ratios provided information upon increased cellularity, mitoses and cellular atypism, and facilitated diagnosis. Pathologic samples taken from areas of increased Lac/Cr ratio showed predominant feature of necrosis. (1)H CSI was feasible with the stereotactic headframe in place. The final pathologic results obtained were concordant with the local metabolic information from (1)H CSI. We believe that (1)H CSI-directed stereotactic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting.  相似文献   

20.
双氢埃托啡(1)为合成的新型高效镇痛药.其~1H和~(13)C NMR谱较为复杂,本文采用二维~1H—~1H COSY—NO ESY和~(13)C—~1H COSY等技术作了研究,确定了其全部~1H和~(13)C谱峰的归属,推断出C—7的构型,并且发现前人对其类似物的一些谱峰指定有误.本结果有助于此类化合物的结构测定和立体化学的研究.  相似文献   

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