Conjugated Systems Containing Antiaromatic Cyclobutadienoids: Synthesis and Study of the Multifaceted Effects of Local Antiaromaticity

斯坦福大学化学系的夏岩教授在化学系化学结构、动力学和机制B项目资助下，正在开发一个富含碳的不同家族的共轭分子，这些分子含有不寻常的反芳香环丁二烯（CBDs），以控制和理解反芳香性的复杂效应，为未来的有机电子应用提供帮助。共轭分子是各种光学和电子应用的关键材料。虽然它们主要由芳香族框架组成，但长期以来，引入CBD反芳香族基序一直被视为一种获得良好分子特性的新策略，但共轭CBD以前很难获得。该研究将产生一系列前所未有的含cbd共轭分子，对抗芳性的控制和影响有新的基本见解，以及新型的共轭材料。该项目整合了有机合成、设计和共轭材料的先进物理测量以及计算，为斯坦福大学和湾区的研究生、本科生和高中学生提供了一个高度跨学科和协作的培训和推广环境。富碳共轭分子因其光电特性和应用而具有重要的基础和技术意义。含有4个pi-电子的反芳香环丁二烯类化合物（CBD）共轭体系的合成具有挑战性，从而限制了对CBD在扩展pi-体系中多方面作用的理解。该项目将利用夏教授团队最近开发的方法，合成几种具有不同拓扑结构、共轭大小、构象和电子特性的含cbd多环共轭烃系列。这些系列分子的实验和计算研究将回答以下问题：1)如何调节CBD的抗芳香性程度？2)抗芳香性如何影响前沿分子轨道、pi键结构和构象、光电性质和载流子迁移率？3)如何通过设计CBD基序的融合来调整芳香框架的分子性质？该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Yan Xia of the Department of Chemistry at Stanford University is developing a diverse family of carbon-rich conjugated molecules containing unusual antiaromatic cyclobutadienoids (CBDs) to control and understand the complex effects of antiaromaticity for future organic electronic applications. Conjugated molecules are critical materials for various optical and electronic applications. While they predominantly consist of aromatic frameworks, introducing CBD antiaromatic motifs has long been sought as a novel strategy to achieve favorable molecular properties, but conjugated CBDs are previously challenging to access. The proposed research will generate several unprecedented series of CBD-containing conjugated molecules, new fundamental insights into the control and influence of antiaromaticity, and new types of conjugated materials. This project integrates organic synthesis, design and advanced physical measurement of conjugated materials, and computation, providing a highly interdisciplinary and collaborative environment for training and outreach at graduate, undergraduate, and high school levels for students at Stanford and from the Bay Area.Carbon-rich conjugated molecules are of significant fundamental and technical interest for their optoelectronic properties and applications. Conjugated systems containing 4 pi-electron antiaromatic cyclobutadienoids (CBDs) have been challenging to synthesize, thus limiting the understanding of the multifaceted effects of CBD in extended pi-systems. This project will leverage the methodology that the Professor Xia's group has recently developed to synthesize several series of CBD-containing polycyclic conjugated hydrocarbons with different topologies, sizes of conjugation, conformations, and electronic characteristics. Experimental and computational investigations of these series of molecules will be carried out to answer the following questions: 1) How to modulate the degree of CBD antiaromaticity? 2) How does antiaromaticity affect frontier molecular orbitals, pi-bonding structures and conformations, optoelectronic properties, and carrier mobility? 3) How to tune these molecular properties of aromatic frameworks by designed fusion of CBD motifs?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.