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

在该项目中，由化学系化学结构，动力学机制B计划资助，斯坦福大学化学系的Yan Xia教授正在开发一个包含不寻常的反芳香环丁二烯（CBD）的富碳共轭分子的多样性家族，以控制和理解反芳香性的复杂效应，用于未来的有机电子应用。 共轭分子是各种光学和电子应用的关键材料。虽然它们主要由芳族框架组成，但引入CBD反芳族基序长期以来一直被视为实现有利分子性质的新策略，但缀合的CBD先前具有挑战性。拟议的研究将产生几个前所未有的含CBD的共轭分子系列，对反芳香性的控制和影响的新的基本见解，以及新型共轭材料。该项目整合了有机合成、共轭材料的设计和先进物理测量以及计算，为斯坦福大学和湾区的学生提供了一个高度跨学科和协作的环境，用于研究生、本科生和高中生的培训和推广。富碳共轭分子的光电特性和应用具有重要的基础和技术意义。含有4 π-电子反芳环丁二烯（CBD）的共轭体系的合成具有挑战性，从而限制了对CBD在扩展π-体系中的多方面影响的理解。该项目将利用夏教授团队最近开发的方法来合成几个系列的具有不同拓扑结构，共轭大小，构象和电子特性的含CBD的多环共轭烃。这些系列分子的实验和计算研究将进行回答以下问题：1）如何调节CBD反芳香性的程度？2)反芳香性如何影响前线分子轨道、π键结构和构象、光电性质和载流子迁移率？3)如何通过CBD基序的设计融合来调节芳香框架的这些分子性质？该奖项反映了NSF的法定使命，并被认为是值得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的支持。

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.