相关实验视频

Updated: Jul 9, 2025

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

Published on: September 12, 2018

现场逐步扫描的固态127INMR的1,4-二二多二

Kazuhiko Yamada¹, Tatsuo Kaiho²

¹Interdisciplinary Science Unit, Multidisciplinary Sciences Cluster, Research and Education Faculty, Kochi University, Oko Campus, Nankoku, Kochi, 783-8505, Japan.

Solid state nuclear magnetic resonance

|December 6, 2023

概括

固态127I核四极共振 (NQR) 实验在1,4-二二多上进行. 该研究确定了90K的四极合常数和不对称参数,证实了实验结果.

科学领域:

固态核磁共振 (NMR) 光谱学
量子化学是一个量子化学.
材料科学材料科学材料科学

背景情况:

核四极共振 (NQR) 光谱是一种强大的技术,用于探测原子核中的电场梯度.
1,4-二多是一种有机化合物,在材料科学中具有潜在的应用,并作为研究素结合的模型系统.

研究的目的:

为了研究1,4-二二多二的固态¹²⁷I NQR特性.
为了确定四极合常量 (C_Q) 和不对称参数 (η_Q) 在1,4-diiodobenzene中的127I.
通过光谱模拟验证实验NQR结果.

主要方法:

进行了127次现场逐步扫描固态NMR实验.
四极卡尔-普尔塞尔梅布姆-吉尔 (QCPMG) 测量是在90K进行的.
频谱模拟涉及对齐曼四极哈密尔顿的数字计算和对角化.

主要成果:

在90K时成功观察了1,4-二二多二的127I NQR光谱.
四极合常数 (C_Q) 确定为1863(5) MHz.
发现不对称参数 (η_Q) 是0.04(2).

结论:

在1,4-二多中对127I NQR的实验结果是一致的和可靠的.
确定的光谱参数为了解1,4-二二多二的电子结构和分子动力学提供了宝贵的信息.
这项研究证明了现场逐步扫描的NMR和QCPMG技术对固态NQR分析的有效性.

关键词:

1,4-二二二二二二二二二二二二二二二二二二二二二二二二二二二二二二二二二二现场逐步扫描的NMR可以通过步骤进行扫描.固态-127的NMR是一种固态-127的NMR.

更多相关视频

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Published on: September 17, 2017

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Published on: May 27, 2018

相关概念视频

NMR Spectroscopy of Benzene Derivatives

NMR Spectroscopy of Benzene Derivatives

Simple unsubstituted benzene has six aromatic protons, all chemically equivalent. Therefore, benzene exhibits only a singlet peak at δ 7.3 ppm in the 1H NMR spectrum. The observed shift is far downfield because the aromatic ring current strongly deshields the protons. Any substitution on the benzene ring makes the aromatic protons nonequivalent, and the protons split each other. The peak is, therefore, no longer a singlet and the splitting pattern and their associated coupling...

¹H NMR: Complex Splitting

¹H NMR: Complex Splitting

A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.

¹³C NMR: ¹H–¹³C Decoupling

¹³C NMR: ¹H–¹³C Decoupling

The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...