Centro de Química e Bioquímica e Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa , 1749-016 Lisboa, Portugal.
J Phys Chem A. 2013 Oct 31;117(43):11107-13. doi: 10.1021/jp407739h. Epub 2013 Oct 21.
A previously developed OPLS-based all-atom force field for organometallic compounds was extended to a series of first-, second-, and third-row transition metals based on the study of M(CO)(n) (M = Cr, Fe, Ni, Mo, Ru, or W) complexes. For materials that are solid at ambient temperature and pressure (M = Cr, Mo, W) the validation of the force field was based on reported structural data and on the standard molar enthalpies of sublimation at 298.15 K, experimentally determined by Calvet-drop microcalorimetry using samples corresponding to a specific and well-characterized crystalline phase: Δ(sub)H(m)° = 72.6 ± 0.3 kJ·mol(–1) for Cr(CO)(6), 73.4 ± 0.3 kJ·mol(–1) for Mo(CO)(6), and 77.8 ± 0.3 kJ·mol(–1) for W(CO)(6). For liquids, where problems of polymorphism or phase mixtures are absent, critically analyzed literature data were used. The force field was able to reproduce the volumetric properties of the test set (density and unit cell volume) with an average deviations smaller than 2% and the experimentally determined enthalpies of sublimation and vaporization with an accuracy better than 2.3 kJ·mol(–1). The Lennard-Jones (12-6) potential function parameters used to calculate the repulsive and dispersion contributions of the metals within the framework of the force field were found to be transferable between chromium, iron, and nickel (first row) and between molybdenum and ruthenium (second row).
先前开发的基于 OPLS 的全原子力场已扩展到一系列第一、二、三过渡金属，基于 M(CO)(n) (M = Cr、Fe、Ni、Mo、Ru 或 W) 配合物的研究。对于在环境温度和压力下为固态的材料（M = Cr、Mo、W），力场的验证基于报道的结构数据以及在 298.15 K 下通过 Calvet 滴微量热法实验测定的标准摩尔升华焓，使用对应于特定且特征明确的结晶相的样品：Cr(CO)(6) 的 Δ(sub)H(m)° = 72.6 ± 0.3 kJ·mol(–1)，Mo(CO)(6) 的 73.4 ± 0.3 kJ·mol(–1)，以及 W(CO)(6) 的 77.8 ± 0.3 kJ·mol(–1)。对于不存在多晶型或相混合物问题的液体，使用了经过严格分析的文献数据。力场能够以平均偏差小于 2%的方式重现测试集的体积性质（密度和晶胞体积），并以优于 2.3 kJ·mol(–1)的精度重现实验测定的升华焓和蒸发热。用于在力场框架内计算金属的排斥和色散贡献的 Lennard-Jones (12-6) 位能函数参数被发现可在铬、铁和镍（第一行）以及钼和钌（第二行）之间转移。
