Renewing the Warwick 600 MHz Solid-State NMR System: Enabling State of the Art Technique Development and Novel Structural Applications

更新 Warwick 600 MHz 固态核磁共振系统：实现最先进的技术开发和新颖的结构应用

• 批准号: EP/D051908/1
• 负责人: Steven Brown
• 金额: $ 57.46万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD051908%2F1
• 关键词: Renewing; Warwick; 600; MHz; Solid

When scientists investigate problems, like all good detectives they need clues as to what is happening. For a whole range of key problems, techniques that can reveal the local environment around an atom are crucial to provide insight into the structure at this level, which often governs how a material or molecule behaves. Nuclear Magnetic Resonance (NMR) spectroscopy has increased in importance throughout the sciences as it is an element specific probe that can distinguish very small changes in the surroundings of different sites (e.g. the number of corners by which an SiO4 unit is connected in a structure, or the different bonding of carbon, such as the differences between CH3 and CH2). NMR exploits the inherent magnetism of atomic nuclei: like the alignment of a compass needle in the Earth's magnetic field, nuclear magnets have a preferred direction when placed in a strong magnetic field. This preference, however, is weak and a nuclear magnet can be made to change its direction from e.g. aligned with to aligned against the magnetic field, by applying a resonant radio wave, i.e., one whose frequency and hence energy matches precisely the energy required to flip the nuclear magnet. The electrons surrounding the atomic nucleus are also affected by the presence of a magnetic field. Importantly, the resonant frequency of a particular nucleus depends very sensitively on this additional response of the electrons, such that the atomic nuclei act as spies of the local electron environment and hence the specific chemical bonding allowing it to be used to probe environments as described above.The resonant frequencies of different nuclear isotopes are well separated such that an NMR spectrum is specific to a particular chosen isotope. (An element can exist as different isotopes whereby there is the same number of protons but a different number of neutrons in the nucleus - the number refers to the total number of protons and neutrons.) This project will make use of much of the Periodic Table. Some nuclei are easy (such as 13C and 29Si) but others have been rarely observed by NMR (e.g. 33S, 47,49Ti). The project is to provide the state of the art equipment to allow the latest, modern experiments to be implemented and new ones designed. The equipment will be used in conjunction with a high magnetic field, and this makes possible some experiments that are not possible at lower fields because of the increased resolution for some nuclei and larger signal that the system will provide. One of the key plus points for NMR is that nuclei experience interactions that convey precise information about their surroundings. As an example the dipole interaction arises as the nuclear magnets are not isolated, but rather they interact in an analogous way to how two bar magnets either attract or repel when brought close together. Importantly, the magnitude of this so-called dipolar interaction is inversely proportional to the cubed distance between the two nuclear spins. Thus, the measurement of such dipolar interactions between a pair of say 17O and 1H nuclei directly gives the distance between an oxygen and a hydrogen atom. Such a distance can be used to quantify the degree of hydrogen bonding - an interaction that plays a key role in determining, e.g., the three-dimensional structure of a protein.A test of a good technique is that it is applicable to a wide range of problems. The equipment and the techniques developed as part of this project will be applied to both physical and life sciences. Problems to which the atomic scale structural information will be applied include: pharmaceuticals, catalysts for hydrocarbon conversion, volcanic materials, radioactive waste-storage glasses, new tissue replacement materials, understanding diseases and enzyme pathways and new electronic materials. It is through the partnership between problem-based and technique-based scientists that real progress is made.

当科学家调查问题时，就像所有优秀的侦探一样，他们需要有关正在发生的事情的线索。对于一系列关键问题，能够揭示原子周围局部环境的技术对于深入了解该级别的结构至关重要，而该级别的结构通常决定着材料或分子的行为方式。核磁共振 (NMR) 光谱在整个科学领域中的重要性与日俱增，因为它是一种元素特异性探针，可以区分不同位点周围环境的微小变化（例如，结构中连接 SiO4 单元的角数，或碳的不同键，例如CH3和CH2之间的差异）。核磁共振利用了原子核的固有磁性：就像指南针在地球磁场中的对准一样，核磁体在置于强磁场中时具有首选方向。然而，这种偏好很弱，可以使核磁体改变其方向，例如从通过施加谐振无线电波，即其频率和能量与翻转核磁体所需的能量精确匹配的无线电波，与磁场对齐。原子核周围的电子也会受到磁场的影响。重要的是，特定原子核的共振频率非常敏感地取决于电子的这种附加响应，使得原子核充当局部电子环境的间谍，因此特定的化学键使其可用于探测如上所述的环境不同核同位素的共振频率被很好地分离，使得 NMR 谱特定于特定的选定同位素。 （一种元素可以以不同的同位素形式存在，其中原子核中的质子数量相同，但中子数量不同 - 该数字是指质子和中子的总数。）该项目将利用元素周期表的大部分内容。有些原子核很容易（例如 13C 和 29Si），但其他原子核很少通过 NMR 观察到（例如 33S、47,49Ti）。该项目旨在提供最先进的设备，以便实施最新的现代化实验和设计新的实验。该设备将与高磁场结合使用，这使得一些在较低磁场下无法进行的实验成为可能，因为某些原子核的分辨率提高了，系统将提供更大的信号。核磁共振的关键优点之一是原子核之间的相互作用可以传递有关其周围环境的精确信息。举个例子，偶极子相互作用是因为核磁体不是孤立的，而是以类似于两个条形磁体靠近时吸引或排斥的方式相互作用。重要的是，这种所谓的偶极相互作用的大小与两个核自旋之间的立方距离成反比。因此，测量一对 17O 和 1H 原子核之间的偶极相互作用可以直接给出氧原子和氢原子之间的距离。这样的距离可用于量化氢键的程度，氢键是一种在确定蛋白质的三维结构等方面发挥关键作用的相互作用。检验一项好技术的标准是它适用于广泛的范围的问题。作为该项目一部分开发的设备和技术将应用于物理和生命科学。原子尺度结构信息将应用的问题包括：药物、碳氢化合物转化催化剂、火山材料、放射性废物储存玻璃、新型组织替代材料、了解疾病和酶途径以及新型电子材料。正是通过基于问题和基于技术的科学家之间的合作，才能取得真正的进展。

项目成果

A High-Resolution 43 Ca Solid-State NMR Study of the Calcium Sites of Hydroxyapatite

羟基磷灰石钙位点的高分辨率 43 Ca 固态核磁共振研究

• DOI: 10.1021/ja710557t
• 发表时间: 2008
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Laurencin D

Alkali environments in tellurite glasses

亚碲酸盐玻璃中的碱性环境

• DOI: 10.1016/j.jnoncrysol.2015.01.023
• 发表时间: 2015
• 期刊: Journal of Non-Crystalline Solids
• 影响因子: 3.5
• 作者: Barney E

Quantifying weak hydrogen bonding in uracil and 4-cyano-4'-ethynylbiphenyl: a combined computational and experimental investigation of NMR chemical shifts in the solid state.

量化尿嘧啶和 4-氰基-4-乙炔基联苯中的弱氢键：固态 NMR 化学位移的计算和实验相结合的研究。

• DOI: 10.1021/ja075892i
• 发表时间: 2008
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Uldry AC