Laboratorium voor Chemische Technologie, Universiteit Gent, Krijgslaan 281 S5, 9000 Gent, Belgium.
Chemistry. 2011 Jun 27;17(27):7656-73. doi: 10.1002/chem.201002422. Epub 2011 May 23.
Key to understanding the involvement of organosulfur compounds in a variety of radical chemistries, such as atmospheric chemistry, polymerization, pyrolysis, and so forth, is knowledge of their thermochemical properties. For organosulfur compounds and radicals, thermochemical data are, however, much less well documented than for hydrocarbons. The traditional recourse to the Benson group additivity method offers no solace since only a very limited number of group additivity values (GAVs) is available. In this work, CBS-QB3 calculations augmented with 1D hindered rotor corrections for 122 organosulfur compounds and 45 organosulfur radicals were used to derive 93 Benson group additivity values, 18 ring-strain corrections, 2 non-nearest-neighbor interactions, and 3 resonance corrections for standard enthalpies of formation, standard molar entropies, and heat capacities for organosulfur compounds and organosulfur radicals. The reported GAVs are consistent with previously reported GAVs for hydrocarbons and hydrocarbon radicals and include 77 contributions, among which 26 radical contributions, which, to the best of our knowledge, have not been reported before. The GAVs allow one to estimate the standard enthalpies of formation at 298 K, the standard entropies at 298 K, and standard heat capacities in the temperature range 300-1500 K for a large set of organosulfur compounds, that is, thiols, thioketons, polysulfides, alkylsulfides, thials, dithioates, and cyclic sulfur compounds. For a validation set of 26 organosulfur compounds, the mean absolute deviation between experimental and group additively modeled enthalpies of formation amounts to 1.9 kJ mol(-1). For an additional set of 14 organosulfur compounds, it was shown that the mean absolute deviations between calculated and group additively modeled standard entropies and heat capacities are restricted to 4 and 2 J mol(-1) K(-1), respectively. As an alternative to Benson GAVs, 26 new hydrogen-bond increments are reported, which can also be useful for the prediction of radical thermochemistry.
理解有机硫化合物在各种自由基化学反应中的作用的关键，如大气化学、聚合、热解等，是对其热化学性质的了解。然而，与碳氢化合物相比，有机硫化合物和自由基的热化学数据记录要少得多。传统上求助于本森基团加和法并没有带来任何安慰，因为只有非常有限数量的基团加和值（GAVs）可用。在这项工作中，使用 CBS-QB3 计算并结合 1D 受阻转子校正，对 122 种有机硫化合物和 45 种有机硫自由基进行了计算，得出了 93 种本森基团加和值、18 种环应变校正值、2 种非最近邻相互作用和 3 种共振校正值，用于有机硫化合物和有机硫自由基的标准生成焓、标准摩尔熵和热容。报告的 GAVs 与以前报道的碳氢化合物和碳氢自由基的 GAVs 一致，其中包括 77 种贡献，其中 26 种自由基贡献，据我们所知，这些贡献以前没有报道过。这些 GAVs 可以用来估计大量有机硫化合物的 298 K 标准生成焓、298 K 标准熵和 300-1500 K 温度范围内的标准热容，即硫醇、硫酮、多硫化物、烷基硫醚、硫醛、二硫代酸酯和环状硫化合物。对于 26 种有机硫化合物的验证集，实验和基团加和模型生成焓之间的平均绝对偏差为 1.9 kJ/mol。对于另外 14 种有机硫化合物，结果表明，计算和基团加和模型标准熵和热容之间的平均绝对偏差分别限制在 4 和 2 J/mol/K。作为本森 GAV 的替代方法，报告了 26 种新的氢键增量，它们也可用于预测自由基热化学。
