Interrogating selectivity in catalysis using molecular vibrations
Interrogating selectivity in catalysis using molecular vibrations
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DOI：
10.1038/nature13019
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发表时间：
2014-03-13
期刊：
影响因子：
64.8
通讯作者：
Sigman, Matthew S.
中科院分区：
文献类型：
--
作者：
Milo, Anat;Bess, Elizabeth N.;Sigman, Matthew S.
作为反应性和选择性基础的分子性质的描述是物理有机化学的核心（1-5），这些知识可以用于设计改进的合成方法或识别新的化学转化（6-9）。因此，影响反应性和选择性趋势的性质的数学表示，即分子参数，是至关重要的。通过将这些分子参数与实验结果等同而产生的相关性通常被定义为自由能关系，并可用于评估选择性的起源，并产生新的、可通过实验验证的假设（6，10 -12）。这种类型的成功关联背后的前提是，系统扰动的分子性质影响催化剂、底物和参与选择性测定的任何反应组分之间的过渡态相互作用（10，11）。经典的物理有机分子描述符，如Hammett（4）、塔夫脱（3）或Charton（5）参数，试图独立探测孤立的电子或空间效应（3- 6、13、14）。然而，这些参数不能解决同时的，非加性的变化超过一个分子特性，这限制了他们的效用。在这里，我们报告了一个参数系统的基础上的振动响应的分子，红外辐射，可用于数学模型和预测的选择性趋势的相互关联的空间和电子效应的反应在感兴趣的位置。所公开的参数系统是机械地导出的，并且应该在化学和生物系统的研究中找到广泛的用途。
The delineation of molecular properties that underlie reactivity and selectivity is at the core of physical organic chemistry(1-5), and this knowledge can be used to inform the design of improved synthetic methods or identify new chemical transformations(6-9). For this reason, the mathematical representation of properties affecting reactivity and selectivity trends, that is, molecular parameters, is paramount. Correlations produced by equating these molecular parameters with experimental outcomes are often defined as free-energy relationships and can be used to evaluate the origin of selectivity and to generate new, experimentally testable hypotheses(6,10-12). The premise behind successful correlations of this type is that a systematically perturbed molecular property affects a transition-state interaction between the catalyst, substrate and any reaction components involved in the determination of selectivity(10,11). Classic physical organic molecular descriptors, such as Hammett(4), Taft(3) or Charton(5) parameters, seek to independently probe isolated electronic or steric effects(3-6,13,14). However, these parameters cannot address simultaneous, non-additive variations to more than one molecular property, which limits their utility. Here we report a parameter system based on the vibrational response of a molecule to infrared radiation that can be used to mathematically model and predict selectivity trends for reactions with interlinked steric and electronic effects at positions of interest. The disclosed parameter system is mechanistically derived and should find broad use in the study of chemical and biological systems.