Nuclear magnetic resonance spectrometer for measurements at elevated pressures

压力是基本物理参数，通常可用于i）调节化学过程的动力学和热力学，以及ii）阐明下至键形成和键制动的分子水平的反应机制。我们的团队长期致力于研究高压（高达2 kbar）的应用，特别是结合NMR技术，研究与生物、催化、环境或能量转换相关的溶液中的反应。在此应用的用于在高压下测量的NMR光谱仪应该使我们能够在除了高压之外的各种条件下进行多功能的机理研究，这些条件包括：i）在可变和低温下操作（153 K至373 K），ii）在水性和有机溶剂中的测量，iii）氧和/或光敏样品，iv）生物/医学样品，V）单相（液体）或两相这种相当罕见的设置的应用超出了NMR技术的标准使用，并且将主要涉及机械压力依赖性研究以确定活化和/或反应体积，用于过渡态的“可视化”，反应中间体的表征，溶液中的动态过程和平衡（例如，金属中心的水交换，配位平衡、自旋平衡、主客体平衡）。为了实现这些极具挑战性的研究任务，要求NMR光谱仪在高压下提供高分辨率和高灵敏度的测量，500 MHz磁体将是最佳选择。由于我们研究了广泛的有机分子和生物大分子，因此除了1H和19 F外，具有Z梯度的5 mm多核宽带双共振探针对13 C，17 O，31 P和57 Fe的灵敏度将是最佳的。然而，所申请的仪器的最基本特征是其与两种不同的高压设置的兼容性：i）一种市售（用于含水样品或两相（气-液）实验）和（ii）另一个将是自制的高压NMR探针（基于我们已经用于对光/氧敏感样品进行更复杂测量的系统，各种有机溶剂和低温下）。这种高压NMR仪器具有独特的性能，能够在非常不同的条件下进行多学科相关的机理研究，据我们所知，在慕尼黑地区的LMU和这种组合中，甚至在德国都不存在。这样的设备对于我们正在进行和计划中的项目是不可或缺的，并且有可能为生物无机化学，生物化学，催化和化学能量转换领域的国际研究合作做出贡献。

Pressure is a basic physical parameter that can generally be used i) to modulate kinetics and thermodynamics of chemical processes and ii) to elucidate reaction mechanisms down to the molecular level of bond-making and bond-braking. Our group has a long-term research interest and expertise in applying high pressures (up to 2 kbar) for both purposes, in particularly in combination with NMR technique for investigations of reactions in solutions that are of biological, catalytic, environmental or energy-conversion relevance. The herewith applied-for NMR spectrometer for measurements at elevated pressures should enable our versatile mechanistic research under diverse conditions that in addition to high pressures include: i) operation at variable and low temperatures (153 K to 373 K), ii) measurements in aqueous and organic solvents, iii) oxygen and/or light sensitive samples, iv) biological/medical samples, v) one- (liquid) or two-phase (liquid-gas) systems, etc. The application of such a rather rare set-up is beyond standard use of NMR technique and will predominantly involve mechanistic pressure-dependent studies to determine activation and/or reaction volumes, for “visualization” of transition states, characterization of reaction intermediates, dynamic processes and equilibria in solutions (e.g. water exchange at metal centers, coordination-, spin-, host-guest-equilibria). For realisation of these quite challenging research tasks the requested NMR spectrometer should provide high resolution and sensitivity for measurement under high pressures, for which a 500 MHz magnet would be the best choice. Since we investigate a broad range of (in)organic molecules and (bio)macromolecules, a 5 mm multinuclear broad band double-resonance probe with Z-gradient, which in addition to 1H and 19F displays high sensitivity for the nuclei 13C, 17O, 31P and 57Fe would be optimal. The most essential feature of the applied-for instrumentation, however, is its compatibility with two different high-pressure setups i) one commercially available (for aqueous samples or two-phase (gas-liquid) experiments) and (ii) another that will be a home-made high-pressure NMR probe (based on the system already used by us for more sophisticated measurements with light/oxygen sensitive samples, various organic solvents and at low temperatures). Such a high-pressure NMR instrument, with unique performances that enable mechanistic studies of multidisciplinary relevance under very diverse conditions, does not exist at LMU, in the area of Munich and in this combination, to best of our knowledge, not even in Germany. Such a device is indispensable for our ongoing and planned projects, and also has the potential to contribute to the international research collaborations in the fields of bioinorganic chemistry, biological chemistry, catalysis and chemical energy conversion.