金属卟啉在催化氧化邻硝基甲苯制取邻硝基苯甲醛反应中定量结构与选择性关系

Quantitative structure-selectivity relationship of metalloporphyrins in catalytic oxidation of o-nitrotoluene to o-nitrobenzaldehyde

设计、合成了49个不同结构的金属卟啉催化剂,使用密度泛函方法计算了其几何结构、电荷分布、前线轨道等9种量子化学参数。同时以金属卟啉催化氧气液相氧化邻硝基甲苯制取邻硝基苯甲醛为模型反应,研究了不同结构的金属卟啉对邻硝基苯甲醛选择性的影响。将两者组合,通过逐步回归分析方法找到了影响邻硝基苯甲醛选择性的主要因素,并建立了定量金属卟啉结构与邻硝基苯甲醛选择性关系方程。结果表明:金属离子的Mulliken电荷、静电势和分子的最低空轨道能量是影响邻硝基苯甲醛选择性的主要因素。经实验验证,所建定量结构与选择性关系方程可用于指导设计高选择性的金属卟啉催化剂。

49 metalloporphyrins were designed and synthesized, and 9 quantum chemical parameters of them, such as geometric structure, charge distribution and the frontier molecular orbital etc, were calculated by using density functional method. Using the catalytic oxidation of o-nitrotoluene to o-nitrobenzaldehyde as a model reaction, effect of metalloporphyrin structures on the selectivity of o-nitrobenzaldehyde was investigated. Main factors that affected the selectivity were found out via stepwise regression analysis method, and a quantitative structure-selectivity relationship equation was effectively established. Results showed that the Mulliken charge and the electrostatic potential of metal ions, the energy of the lowest unoccupied molecular orbital were the main factors affecting the selectivity of o-nitrobenzaldehyde. This metalloporphyrins with equation could be used to provide a theoretical guidance to design high selectivity.