Department of Chemistry, 312 Natural Sciences Complex, State University of New York, Buffalo, New York 14260-3000, USA.
J Am Chem Soc. 2010 Mar 17;132(10):3472-83. doi: 10.1021/ja9096863.
Ab initio molecular dynamics (aiMD) simulations based on density functional theory (DFT) were performed on a set of five anionic platinum complexes in aqueous solution. (195)Pt nuclear magnetic shielding constants were computed with DFT as averages over the aiMD trajectories, using the two-component relativistic zeroth-order regular approximation (ZORA) in order to treat relativistic effects on the Pt shielding tensors. The chemical shifts obtained from the aiMD averages are in good agreement with experimental data. For Pt(II) and Pt(IV) halide complexes we found an intermediate solvent shell interacting with the complexes that causes pronounced solvent effects on the Pt chemical shifts. For these complexes, the magnitude of solvent effects on the Pt shielding constant can be correlated with the surface charge density. For square-planar Pt complexes the aiMD simulations also clearly demonstrate the influence of closely coordinated non-equatorial water molecules on the Pt chemical shift, relating the structure of the solution around the complex to the solvent effects on the metal NMR chemical shift. For the complex Pt(CN)(4), the solvent effects on the Pt shielding constant are surprisingly small.
基于密度泛函理论（DFT）的从头算分子动力学（aiMD）模拟在一组五组阴离子铂配合物在水溶液中进行。使用二分量相对论零阶正则逼近（ZORA）来处理对 Pt 屏蔽张量的相对论效应，通过 aiMD 轨迹平均计算（195）Pt 核磁共振屏蔽常数。从 aiMD 平均值获得的化学位移与实验数据吻合良好。对于 Pt(II)和 Pt(IV)卤化物配合物，我们发现与配合物相互作用的中间溶剂壳层对 Pt 化学位移有显著的溶剂效应。对于这些配合物，溶剂对 Pt 屏蔽常数的影响程度可以与表面电荷密度相关联。对于平面正方形 Pt 配合物，aiMD 模拟还清楚地表明了紧密配位的非赤道水分子对 Pt 化学位移的影响，将配合物周围溶液的结构与金属 NMR 化学位移的溶剂效应联系起来。对于Pt(CN)(4)配合物，对 Pt 屏蔽常数的溶剂效应出奇地小。
