运用信息理论发展密度泛函活性理论

Historically called conceptual density functional theory, density functional reactivity theory (DFRT) uses only variables derived from the electron density and its gradient to quantify chemical structural and reactivity properties of molecules. Though gradually accepted by the chemical community and widely applied to a variety of problems, the present version of DFRT is based upon and thus limited by the first and second order derivatives from the Taylor expansion of the total electronic energy with respect to the electron number and external potential. In this proposal, we call for new developments of this theory by expanding its scope. To that end, we propose to incorporate the information theory into DFRT, because Shannon entropy, Fisher information and information gain et al. are the key quantities in information theory, which employ only the electron density and its gradient. As proof of concept, in the past year, we have published a series of papers and demonstrated its feasibility and reliability. In this propose, we will continue to study the quantities of information theory and their applications in predicting chemical structural and reactivity properties at the both molecular and atomic levels. Using various atomic partition schemes, we will investigate different bonding schemes and different chemical processes and find their changing patterns. We will also correlate their behaviors with those from other reactivity indices in DFRT, especially electrophilicity and nucleophilicty. We will additionally explore the possibility of applying these quantities in predicting regioselectivity and steroselectivity of chemical reactions. Put together, the seamless accomplishment of these tasks will shed new lights to the development of DFRT, and provide our contributions to the eventual maturity and perfection of this brand new reactivity theory.

密度泛函活性理论(DFRT)，又称为概念密度泛函理论，运用只与电子密度及其梯度等相关的变量定量地描述和预测分子的结构和反应活性。DFRT虽取得了长足进展并日益被广泛应用，但其目前框架仅局限于体系总能量对电子数和外势泰勒展开得到的一阶或多阶微商。本项目主张扩大其理论范畴，推广其应用领域，提出将信息理论纳入DFRT的框架之中，因为香农熵、费舍尔信息及信息增益量等信息理论变量均只与电子密度及其梯度有关。为此，在过去两年间我们已经取得了初步成果，发表了一系列论文证明了其可行性和可靠性。本项目将继续系统地研究信息理论变量在揭示分子稳定性和反应活性中的作用，探讨不同键合和化学过程中它们的变化规律。同时，研究它们与DFRT中其他活性指标，特别是亲电亲核活性的关联，以及在预测区域选择性和立体选择性中的应用。本项目的顺利完成将为DFRT的发展提供新的思路，也将为DFRT的最终成熟和完善做出我们的贡献。

密度泛函活性理论(DFRT)，又称为概念密度泛函理论，运用只与电子密度及其梯度等相关.的变量定量地描述和预测分子的结构和反应活性。本项目主张扩大DFRT理论范畴，推广其应用领域，将信息理论（ITA）纳入DFRT的框架之中。项目研究中，把各信息理论物理量引入DFRT中作为化学活性的定性定量描述符，同时提出描述强共价相互作用的指数（SCI）和描述立体效应的电子力（Fe）、空间力（Fs）、空间电荷（qe）新的化学概念定量描述参量等。这既丰富了ITA-DFRT的理论体系，也提高了其对化学活性定量描述的能力。实现了用ITA方法对分子体系的总能量、能量分量等电子性质的准确拟合。在对分子性质和反应活性应用方面，已经公开发表的相关研究成果包括有：SN2反应能垒、酸碱性、异端效应、芳香性、立体效应、协同性、富勒烯异构化能、强共价相互作用等。与传统的片段加合法和基团加和法等定量结构性能关系相比，ITA-DFRT不仅实现了直接用电子密度对这些理化性质的定量描述，而且对这些性质提供了新的认识。如在芳香性的研究中发现基态的Hückel规则（4n+2和4nπ电子分别对应芳香性和反芳香性）和激发态的Baird规则（4n+2和4nπ电子分别对应反芳香性和芳香性）具有相同的理论本质。本项目资助主要成员刘述斌成功主办第七届海峡两岸理论与计算化学会议，首届理论与计算中的化学概念国际研讨会，客座编辑《物理化学学报》特刊《密度泛函理论中的化学概念特刊》。项目资助举办的本领域学术会议、项目参与人参与学术会议、邀请专家学术讲座人次、发表论文数量、培养学生人数都超过预期。已顺利完成项目预定的各项目标。