Wilhelm M, Feng H, Tracht U, Spiess H W
Max-Planck-Institut für Polymerforschung, Mainz, D-55021, Germany.
J Magn Reson. 1998 Oct;134(2):255-60. doi: 10.1006/jmre.1998.1512.
A new 2D solid-state CP/MAS 13C NMR exchange experiment for through-space isotropic chemical shift correlation is proposed and demonstrated. Through-space correlation is established via a second cross polarization from 13C to 1H and subsequent 1H spin diffusion. A third cross polarization results in the final 13C-13C isotropic chemical shift correlation. The 1H spin diffusion time is a variable parameter allowing different mean square magnetization displacements to be probed. Experimental results on mixtures of differently 13C-labeled alanine and polyethylene indicate that this site-selective 2D technique can be used to characterize domain sizes and proximities over a wide range of length scales (1-200 nm) in solids such as polymers or biological materials.
提出并演示了一种用于空间各向同性化学位移相关的新型二维固态CP/MAS 13C NMR交换实验。通过从13C到1H的第二次交叉极化以及随后的1H自旋扩散建立空间相关性。第三次交叉极化产生最终的13C-13C各向同性化学位移相关。1H自旋扩散时间是一个可变参数，允许探测不同的均方磁化位移。对不同13C标记的丙氨酸和聚乙烯混合物的实验结果表明，这种位点选择性二维技术可用于表征聚合物或生物材料等固体中广泛长度尺度（1-200 nm）上的畴尺寸和接近度。
