Structure and Dynamics in Disordered Solids

威廉和玛丽学院的吉娜·霍特森教授和罗伯特·沃尔德教授是由实验物理化学项目资助的，他们对无序固体进行实验核磁共振研究。其中一个项目涉及研究固体晶体形式的氨基酸和环二肽以及环糊精疏水空腔中的络合物的结构、无序和动力学。后一种环境旨在作为生物系统的模型。多肽和蛋白质的无序性问题很重要，因为许多系统，如淀粉样变性蛋白和膜蛋白都表现出严重的无序性，到目前为止很难研究。另一个项目涉及无机铁电材料的研究。其中一些材料表现出特殊的压电和电子性能，这些影响的来源尚不清楚。对混合钙钛矿的研究将检验离子无序和运动是不寻常介电效应的原因这一假设。PI建议测量有机络合物的动态线形和松弛2H核磁共振和13C-15N红色距离测量。他们还建议使用93Nb/45Sc高分辨率MQMAS研究无机弛豫剂。这项工作将使我们能够在给出微观细节的测量的基础上，理解两类无序固体的宏观行为。主客体化学将会引起蛋白质结构化学家的兴趣，因为他们试图了解许多仍未解决的蛋白质的结构。钙钛矿材料的研究对新型陶瓷电子材料的发展具有潜在的影响。这项工作中有相当一部分致力于开发新的核磁共振方法，这些方法最终可能在卫生和材料领域受益。

Professors Gina Hoatson and Robert Vold of the College of William and Mary are funded by the Experimental Physical Chemistry program to perform experimental Nuclear Magnetic Resonance studies on disordered solids. One project involves study of the structure, disorder and dynamics of amino acids and cyclic dipeptides in the solid crystalline form and as complexes in the hydrophobic cavities of cyclodextrin. The latter environment is intended as a model for biological systems. The issue of disorder in peptides and proteins is important since a number of systems such as amyloidiogenic proteins and membrane proteins all show significant disorder and are to date difficult to study. The other project involves the investigation of inorganic ferroelectrics. Some of these materials display exceptional piezoelectric and electronic properties, and the origin of these affects is not understood. Studies of mixed perovskites will test the hypothesis that ion disorder and motion are responsible for the unusual dielectric effects. The PIs propose to measure dynamic line shape and relaxation 2H NMR and 13C-15N REDOR distance measurements on the organic complexes. They also propose to use 93Nb/45Sc high resolution MQMAS studies on the inorganic relaxors. This work will allow understanding of the macroscopic behaviors of two classes of disordered solids, based on measurements that give microscopic details. The host-guest chemistry will be of interest to protein structure chemists, as they attempt to understand the structures of the many proteins still not solved. The perovskite work has potential impact on the development of new ceramic electronics materials. There is a considerable component in this work dedicated to developing new nuclear magnetic resonance methods that ultimately could be of benefit in the health and materials fields.