Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario, K1N 6N5, Canada.
Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario, K1N 6N5, Canada.
Solid State Nucl Magn Reson. 2019 Oct;102:53-62. doi: 10.1016/j.ssnmr.2019.07.004. Epub 2019 Jul 25.
The design and implementation of a software package for the analysis of single-crystal NMR data is presented. The SCFit software can treat spectra arising from various interactions: (i) chemical shift tensor only; (ii) chemical shift tensor and quadrupolar coupling tensor; (iii) dipolar and indirect nuclear spin-spin coupling tensors; (iv) all four interactions. The software is demonstrated on recently reported O and P single-crystal NMR data for triphenylphosphine oxide and for two of its halogen-bonded cocrystals. The O single-crystal NMR data represent a case where all four above-mentioned interactions simultaneously affect the spectra. SCFit can fit the chemical shift and quadrupolar coupling in two ways: (i) through an unconstrained fitting process where all tensor parameters are freely optimized or (ii) through a constrained fitting process where the principal components of the tensors may be fixed to values known previously with high precision via the analysis of powder samples. The second strategy is explored in an effort to reduce the number of unknowns in the fitting process; an improvement in the precision of the resulting tensor orientations is noted in some cases.
介绍了用于分析单晶 NMR 数据的软件包的设计和实现。SCFit 软件可以处理来自各种相互作用的光谱：（i）仅化学位移张量；（ii）化学位移张量和四极耦合张量；（iii）偶极和间接核自旋-自旋耦合张量；（iv）所有四个相互作用。该软件在最近报道的三苯基氧化膦及其两个卤键共晶的 O 和 P 单晶 NMR 数据上进行了演示。O 单晶 NMR 数据代表了上述所有四个相互作用同时影响光谱的情况。SCFit 可以通过两种方式拟合化学位移和四极耦合：（i）通过无约束拟合过程，其中所有张量参数均可自由优化，或（ii）通过约束拟合过程，其中张量的主分量可以通过粉末样品分析以前高精度确定的值固定。探索了第二种策略以减少拟合过程中的未知数数量；在某些情况下，注意到所得张量方向的精度有所提高。
