Bursch Markus, Gasevic Thomas, Stückrath Julius B, Grimme Stefan
Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany.
Inorg Chem. 2021 Jan 4;60(1):272-285. doi: 10.1021/acs.inorgchem.0c02907. Epub 2020 Dec 15.
A comprehensive and diverse benchmark set for the calculation of Si NMR chemical shifts is presented. The set includes 100 silicon containing compounds with 146 experimentally determined reference Si NMR chemical shifts measured in nine different solvents in a range from -400 to +828 ppm. Silicon atoms bound to main group elements as well as transition metals with coordination numbers of 2-6 in various bonding patterns including multiple bonds and coordinative and aromatic bonding are represented. The performance of various common and specialized density functional approximations including (meta-)GGA, hybrid, and double-hybrid functionals in combination with different AO basis sets and for differently optimized geometries is evaluated. The role of scalar-relativistic effects is further investigated by inclusion of the zeroth order regular approximation (ZORA) method into the calculations. GGA density functional approximations (DFAs) are found to outperform hybrid DFAs with B97-D3 performing best with an MAD of 7.2 ppm for the subset including only light atoms ( < 18), while TPSSh is the best tested hybrid functional with an MAD of 10.3 ppm. For Si cores in the vicinity of heavier atoms, the application of ZORA proved indispensable. Inclusion of spin-orbit effects into the Si NMR chemical shift calculation decreases the mean absolute deviations by up to 74% compared to calculations applying effective core potentials.
本文提出了一个用于计算硅核磁共振化学位移的全面且多样的基准集。该基准集包含100种含硅化合物，在9种不同溶剂中测量了146个实验测定的参考硅核磁共振化学位移，范围从-400至+828 ppm。该基准集涵盖了与主族元素以及过渡金属键合的硅原子，其配位数为2至6，呈现出多种键合模式，包括多重键、配位键和芳香键。评估了各种常见和专门的密度泛函近似方法，包括（元）广义梯度近似（GGA）、杂化泛函和双杂化泛函，这些方法与不同的原子轨道基组以及不同优化几何结构相结合的性能。通过在计算中纳入零阶正则近似（ZORA）方法，进一步研究了标量相对论效应的作用。发现GGA密度泛函近似方法优于杂化密度泛函近似方法，对于仅包含轻原子（<18）的子集，B97-D3表现最佳，平均绝对偏差（MAD）为7.2 ppm，而TPSSh是测试效果最好的杂化泛函，MAD为10.3 ppm。对于靠近重原子的硅核，ZORA方法的应用被证明是不可或缺的。与应用有效核势的计算相比，在硅核磁共振化学位移计算中纳入自旋轨道效应可使平均绝对偏差降低高达74%。
