过渡金属催化反应多自旋态势能面非绝热能量跨度模型的建立与应用

Taking multi-spin states potential surfaces non-adiabatic reaction kinetics theoretical calculation as means and turnover frequency (TOF) research approach proposed by Kozuch is referenced, the non-adibatic factor(intersystem crossing probability, <PISC>) in the catalytic reaction is reasonably introduced to the rate constant M matrix (energy representation ) to deduce the calculation formulas of TOF(turnover frequency of which contains non-adiabatic factor), TON (turnover number of which contains non-adiabatic factor), energetic span δE (apparent activation energy) and FMECP ( the degree of influence of which contains nonadibatic factor). A non-adiabatic energy span model for the transition metal catalytic reactions is established. In order to verify the non-adiabatic energy span model, The transition metal catalyzed spin-forbidden reaction occurs among the small molecules is elected as research system, a series of approaches are adopted to calculated the spin-orbital coupling interaction energy of MECP, the probability of intersystem crossing( PISC ), the Gibbs free energy of intermediates, transition states on multi-spin potential surfaces and minimum energy crossing point (MECP).The M matrix elements Mij are analyzed to reveal the influence laws of non-adiabatic steps for TOF, TON and δE, one method is proposed to judge which is the controlling factors between adiabatic and non-adiabatic steps in the catalytic reaction. It also can serve as the reliable, practical calculating model and analysis method for catalyst selection, design and catalytic reaction dynamics researches.

以多自旋态势能面非绝热动力学理论计算为手段，借鉴Kozuch转换频率（TOF）的研究方法，将过渡金属催化反应中非绝热因素（系间窜越几率<PISC>）合理地引入到速率常数矩阵M（E-表示）中，推演包含非绝热因素<PISC>的TOF、TON(转换数)、能量跨度δE（表观活化能）以及影响度FMECP的计算式，建立包含非绝热因素的过渡金属催化反应能量跨度模型。以过渡金属催化小分子自旋禁阻反应为体系，通过计算过渡金属催化反应在多自旋态势能面上的中间体、过渡态、最低能量交叉点（MECP）的Gibbs自由能、MECP处的自旋-轨道耦合作用能和系间窜越几率等数据，验证和完善非绝热能量跨度模型。通过分析M矩阵元Mij，提出催化反应是由绝热步骤还是非绝热步骤作为控制因素的判断方法，揭示非绝热步骤对TOF、TON、δE的影响规律，为催化剂选择、设计和催化反应动力学研究提供可靠的计算模型和分析方法。

以Kozuch能量跨度模型为基础，根据多自旋态势能面非绝热动力学理论，通过计算多自旋态势能面之间的系间窜越几率，将过渡金属催化反应中非绝热因素（系间窜越几率<PISC>）引入到速率常数矩阵M（E-表示）中，建立了催化循环反应包含非绝热因素<PISC>的能量跨度模型。接着以过渡金属催化小分子自旋禁阻反应为体系，运用新能量跨度模型对循环催化反应的转换频率（TOF）、表观活化能δE进行了计算，确定了循环催化反应的决速过渡态及决速中间体。经实例验证，该模型能够定性地解释催化反应的动力学特征，为催化反应实验研究提供了计算模型和分析方法。研究发现所计算的TOF小的原因是原Kozuch能量跨度模型中所计算的能量跨度δE是其最大值，相应地TOF的计算值是最小的转换频率，因此本项目所建立的新模型也同有此缺陷。为了解决模型存在的问题，我们已花费了很大的精力和时间，因在用Gibbs自由能表示速率常数矩阵M时遇到了数学处理方面的困难，至今未有进展。