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·沃尔德教授由实验物理化学计划资助，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的结构、无序和动力学，以及环糊精疏水空腔中的复合物。 后一种环境旨在作为生物系统的模型。肽和蛋白质中的紊乱问题是重要的，因为许多系统如淀粉样蛋白和膜蛋白都显示出显著的紊乱，并且迄今为止难以研究。 另一个项目涉及无机铁电体的研究。 其中一些材料显示出特殊的压电和电子特性，这些影响的起源尚不清楚。 对混合钙钛矿的研究将检验离子无序和运动是导致不寻常介电效应的假设。 PI建议测量动态线形和弛豫2 H NMR和13 C-15 N REDOR距离测量的有机配合物。 他们还建议使用93 Nb/45 Sc高分辨率MQMAS研究无机弛豫体。 这项工作将允许理解两类无序固体的宏观行为，基于测量，给出微观细节。 主客体化学将是蛋白质结构化学家感兴趣的，因为他们试图了解许多蛋白质的结构仍然没有解决。 钙钛矿的工作对新型陶瓷电子材料的发展具有潜在的影响。 这项工作中有相当大的一部分致力于开发新的核磁共振方法，最终可能在健康和材料领域受益。

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.