Division of Chemical Engineering, Department of Chemical Engineering and Geosciences, Luleå University of Technology, SE 971 87 Luleå, Sweden.
J Phys Chem A. 2011 Mar 3;115(8):1396-407. doi: 10.1021/jp110233d. Epub 2011 Feb 10.
Solid-state (13)C NMR is believed to be a valuable tool for studying adsorption and speciation of xanthates on sulfide mineral surfaces, but to do that, model compounds of possible xanthate species need to be investigated. (13)C NMR chemical shift tensors for molecular fragments of potassium iso-propylxanthate and six of its decomposition products have been determined by combining DFT calculations and (13)C CP/MAS NMR experiments. DFT calculations were performed in NWChem using GIAO method for the NMR shielding tensor calculations. The results of the calculations are in good agreement with experimental data. In the -XCYZ moiety (X, Y, Z = O, S), the more sulfur atoms, the more deshielded the chemical shift becomes and the larger the span of the chemical shift tensor. The δ11 principal value has the largest influence on the span, decreasing when the number of sulfur atoms decreases and the number of oxygen atoms increases. The significant differences in chemical shifts make it possible to distinguish between different species and, hence, in future studies, interpret surface speciation. The tensor parameters can also aid in the interpretation.
固态 (13)C NMR 被认为是研究黄原酸盐在硫化矿物表面吸附和形态的有价值的工具，但要做到这一点，需要研究可能的黄原酸盐物种的模型化合物。通过结合 DFT 计算和 (13)C CP/MAS NMR 实验，确定了异丙基黄原酸钾及其六种分解产物的分子片段的 (13)C NMR 化学位移张量。在 NWChem 中使用 GIAO 方法进行了 NMR 屏蔽张量计算的 DFT 计算。计算结果与实验数据吻合良好。在 -XCYZ 部分（X、Y、Z=O、S）中，硫原子越多，化学位移去屏蔽程度越大，化学位移张量的跨度越大。δ11 主值对跨度的影响最大，当硫原子数量减少和氧原子数量增加时，它会减小。化学位移的显著差异使得区分不同的物种成为可能，因此，在未来的研究中，可以解释表面形态。张量参数也可以辅助解释。
