Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 420088 Kazan, Russia.
Molecules. 2022 Apr 21;27(9):2668. doi: 10.3390/molecules27092668.
In this study, comparative analysis of calculated (GIAO method, DFT level) and experimental P NMR shifts for a wide range of model palladium complexes showed that, on the whole, the theory reproduces the experimental data well. The exceptions are the complexes with the P=O phosphorus, for which there is a systematic underestimation of shielding, the value of which depends on the flexibility of the basis sets, especially at the geometry optimization stage. The use of triple-ζ quality basis sets and additional polarization functions at this stage reduces the underestimation of shielding for such phosphorus atoms. To summarize, in practice, for the rapid assessment of P NMR shifts, with the exception of the P=O type, a simple PBE0/{6-311G(2d,2p); Pd(SDD)}//PBE0/{6-31+G(d); Pd(SDD)} approximation is quite acceptable ( = 8.9 ppm). Optimal, from the point of view of "price-quality" ratio, is the PBE0/{6-311G(2d,2p); Pd(SDD)}//PBE0/{6-311+G(2d); Pd(SDD)} ( = 8.0 ppm) and the PBE0/{def2-TZVP; Pd(SDD)}//PBE0/{6-311+G(2d); Pd(SDD)} ( = 6.9 ppm) approaches. In all cases, a linear scaling procedure is necessary to minimize systematic errors.
在这项研究中，对广泛的钯配合物模型的计算（GIAO 方法，DFT 水平）和实验 P NMR 位移进行了比较分析，结果表明，总体而言，该理论很好地再现了实验数据。例外的是具有 P=O 磷的配合物，对于这些配合物，屏蔽的系统低估，其值取决于基组的灵活性，特别是在几何优化阶段。在该阶段使用三重ζ质量基组和附加极化函数可减少此类磷原子的屏蔽低估。总之，在实践中，对于 P NMR 位移的快速评估，除了 P=O 型之外，简单的 PBE0/{6-311G(2d,2p); Pd(SDD)}//PBE0/{6-31+G(d); Pd(SDD)} 近似是可以接受的（ = 8.9 ppm）。从“价格-质量”比的角度来看，最佳的是 PBE0/{6-311G(2d,2p); Pd(SDD)}//PBE0/{6-311+G(2d); Pd(SDD)}（ = 8.0 ppm）和 PBE0/{def2-TZVP; Pd(SDD)}//PBE0/{6-311+G(2d); Pd(SDD)}（ = 6.9 ppm）方法。在所有情况下，都需要线性缩放程序来最小化系统误差。
