A major part of chemical conversions is carried out in the fluid phase, where an accurate modeling of the involved reactions requires to also take into account solvation effects. Implicit solvation models often cover these effects with sufficient accuracy but can fail drastically when specific solvent–solute interactions are important. In those cases, microsolvation, i.e., the explicit inclusion of one or more solvent molecules, is a commonly used strategy. Nevertheless, microsolvation also introduces new challenges—a consistent workflow as well as strategies how to systematically improve prediction performance are not evident. For the COSMO and COSMO-RS solvation models, this work proposes a simple protocol to decide if microsolvation is needed and how the corresponding molecular model has to look like. To demonstrate the improved accuracy of the approach, specific application examples are presented and discussed, i.e., the computation of aqueous pK_a values and a mechanistic study of the methanol mediated Morita–Baylis–Hillman reaction.

化学转化的主要部分是在液相中进行的，其中所涉及反应的准确建模还需要考虑溶剂化效应。隐式溶剂化模型通常以足够的精度覆盖这些影响，但当特定的溶剂 - 溶质相互作用很重要时可能会严重失败。在这些情况下，微溶剂化，即明确包含一个或多个溶剂分子，是一种常用的策略。然而，微溶剂化也带来了新的挑战——一致的工作流程以及如何系统地提高预测性能的策略并不明显。对于 COSMO 和 COSMO-RS 溶剂化模型，这项工作提出了一个简单的协议来决定是否需要微溶剂化以及相应的分子模型的外观。甲醇介导的 Morita-Baylis-Hillman 反应_的数值和机理研究。