Havlin R H, Park G H J, Pines A
Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
J Magn Reson. 2002 Jul;157(1):163-9. doi: 10.1006/jmre.2002.2571.
We present the first application of switched angle spinning (SAS) to correlate the first-order dipolar spectrum of a liquid crystalline sample with the isotropic magic angle spinning (MAS) spectrum in a two-dimensional experiment. In this experiment we are able to select the degree of dipolar couplings introduced via mechanical manipulations of the liquid crystal director in a single oriented sample. The (19)F SAS-COSY correlation of iodotrifluoroethylene, an AMX spin system, dissolved in the nematic liquid crystal 4-octylphenyl-2-chloro-4-(4-heptylbenzoyloxy)-benzoate provides assignment of both the J and dipolar couplings in a single experiment. This work demonstrates the use of oriented samples and sample spinning to resolve homonuclear dipolar couplings using isotropic chemical shifts.
我们展示了切换角旋转（SAS）在二维实验中的首次应用，该应用将液晶样品的一阶偶极谱与各向同性魔角旋转（MAS）谱相关联。在这个实验中，我们能够通过对单个取向样品中的液晶指向矢进行机械操作来选择引入的偶极耦合程度。溶解在向列型液晶4-辛基苯基-2-氯-4-（4-庚基苯甲酰氧基）苯甲酸酯中的碘三氟乙烯（一种AMX自旋体系）的（19）F SAS-COSY相关性在单个实验中实现了J耦合和偶极耦合的归属。这项工作展示了使用取向样品和样品旋转，通过各向同性化学位移来解析同核偶极耦合。
