Nuclear Magnetic Resonance Studies of Molecular Structure and Dynamics

该研究计划描述了一个计划，以调查科学界根本感兴趣的材料的详细结构和动力学。 广泛的材料将被研究，包括混合钙钛矿是太阳能电池的基石，天然产物和药物在医学上是重要的，过渡金属络合物，其中一些催化化学反应，并具有重要的工业应用。 我们研究材料结构和动力学的主要实验工具是核磁共振光谱，这是MRI（磁共振成像）的基础。 我们研究的许多天然产品，例如，姜黄素具有强氢键，该氢键在决定其分子结构以及因此决定其分子性质方面起着基本作用。 在这些分子与分子内氢键，我们最近观察到氘同位素的NMR化学位移的影响，在固态，我们相信有可能提供详细的信息，氢原子的位置，信息难以获得的X射线衍射。我们正在与理论家合作，计算具有不对称双阱势面的系统的精确势和零点能量。 值得一提的是，美国FDA已经批准了第一个氘标记的药物tetrabenazine-d 6用于人类。 我们在甲基碘化铅铵方面拥有丰富的经验，这种化合物属于一类被称为有机-无机混合钙钛矿的化合物。 虽然我们在1985年就开始使用这种材料，但在韦伯首次制备后不久，直到2009年才意识到这种材料可以用于将太阳能转化为电能。 2009年，太阳能转化为电能的效率约为3.8%，但现在，通过精心控制制备过程，效率已超过22%。 今天，我们加入了许多研究小组，仔细研究相关的有机-无机钙钛矿材料作为太阳能应用的可能候选者。 从最近的文献中，似乎很清楚，阳离子和卤素离子动力学显着影响这些材料的性能。 我们计划使用机械化学合成方法制备几种铅混合卤化物钙钛矿，并使用固态NMR表征阳离子和阴离子动力学。

The research proposal describes a program to investigate the detailed structure and dynamics of materials that are of fundamental interest to the scientific community. A wide range of materials will be investigated including hybrid perovskites that are building blocks of solar cells, natural products and pharmaceuticals that are important in medicine, and transition metal complexes, some of which catalyze chemical reactions and have important industrial applications. Our principal experimental tool for investigating the structure and dynamics of materials is nuclear magnetic resonance spectroscopy, a general tool upon which MRI, magnetic resonance imaging, is based. Many of the natural products that we examine, e.g., curcumin, have strong hydrogen bonds that play a fundamental role in determining their molecular structure and hence their molecular properties. In these molecules with intramolecular hydrogen bonds we have very recently observed deuterium isotope effects on NMR chemical shifts in the solid state that we believe have the potential to provide detailed information about the positions of hydrogen atoms, information difficult to obtain by X-ray diffraction. We are working with theoreticians to compute accurate potentials and zero-point energies for systems with unsymmetrical double-well potential surfaces. It is interesting to point out that the US FDA has approved the first deuterium-labeled drug, tetrabenazine-d6, for human use. We have extensive experience working with methylammonium lead iodide, a compound that belongs to a class of compounds known as organic-inorganic hybrid perovskites. Although we started working with this material in 1985, not long after it was first prepared by Weber, it was not until 2009 that it was realized that this material could be used to convert solar energy into electrical energy. In 2009, the efficiency of converting solar energy to electrical energy was approximately 3.8 %, but now, by careful control of the preparation procedures, efficiencies in excess of 22% have been achieved. Today, we join many research groups scrutinizing related organic-inorganic perovskite materials as possible candidates for solar energy applications. From the recent literature, it seems clear that the cation and halide ion dynamics significantly influences the performance of these materials. We plan to use mechanochemical synthetic methods to prepare several lead mixed-halide perovskites and characterize both the cation and anion dynamics using solid-state NMR.