Complex Carboranes as Weakly Coordinating yet Functional Anions

复杂碳硼烷作为弱配位但功能性阴离子

• 批准号: 2003418
• 负责人: Vincent Lavallo
• 金额: $ 44.5万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003418&HistoricalAwards=false
• 关键词: Complex; Carboranes; Weakly; Coordinating; yet

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Vincent Lavallo of the Department of Chemistry at the University of California-Riverside is developing new classes of ionic compounds with interesting properties. An ionic material is a salt. Professor Lavallo is developing novel ionic materials where both the negatively charged part (anion) and the positively charged (cationic) portion form new materials that may have applications in industries ranging from pharmaceuticals to catalysis to environmental waste remediation. This group has a long history of mentoring high school students from underrepresented groups and will continue and expand these outreach activities. In addition, undergraduate and graduate student researchers will be directly involved in the project and provided with training to prepare them for entry into the workforce in high technology areas.Weakly coordinating anions generally function as spectators with little or no function in chemical reactions. In this project, the implementation of super bulky phosphines and N-Heterocyclic Carbenes (NHC), containing two covalently bound polyhalogenated closo-carborane anions, will be explored as weakly coordinating anions that are also capable of controlled reactivity. The spectator carboranes that flank the phosphine and NHC lone pairs of electrons provide kinetic protection at these reactive sites, enabling the formation of complex ion pairs that contain both a reactive cation and anion. These systems are akin to traditional frustrated Lewis pairs (FLP), except that these species are electrostatically tethered. Such species could achieve more challenging bond activations/group transfers for C-F bond activations, exemplified by the CF bond scission of CF4, a potent greenhouse gas. Additionally, these systems will provide a unique opportunity to isolate the so-called elusive encounter complex in FLP chemistry. These systems will be formed via the solid state hydrogenation of crystalline ion pairs and studied via subsequent analysis via cryo micro electron diffraction. A second embodiment of this project is the exploration of ligand effects on anionic Au(I) hydroamination catalysts, supported by the dianionic phosphines and NHCs. These transition metal anions will be paired with trityl and silylium ions to form reagents capable of generating highly reactive carbocations in the coordination sphere of the metal. Such reactions may lead to a heterolytic oxidative addition and unprecedented low-coordinate alkyl/aryl Au(III) compounds. The targeted Au(III) compounds will have two cis accessible coordination sites and thus may be capable of classical d8 transition metal catalysis. The ability of these species to mediate migratory insertion, carbonylations, as well as other reactions mediated by other low-coordinate D8 metals will be explored.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.

在这个项目中，由化学结构，动力学和机制B计划资助，化学部门，加利福尼亚河畔大学化学系的Vincent Lavallo教授正在开发具有有趣特性的离子化合物的新类别。 离子材料是盐。 Lavallo教授正在开发新型的离子材料，在这些材料中，负电荷的部分（阴离子）和带电的（阳离子）部分形成了新材料，这些材料可能在从药物到催化到环境废物修复的行业中都有应用。该小组有悠久的历史，指导来自代表性不足的小组的高中生，并将继续并扩大这些外展活动。 此外，本科生和研究生研究人员将直接参与该项目，并提供培训，使他们准备进入高科技领域的劳动力。对阴离子的协调通常充当观众，在化学反应中几乎没有功能。 在这个项目中，将实施超笨重的磷和N-杂环碳烯（NHC），其中包含两个共价结合的多面化闭合碳纤维阴离子，将被探索为弱配位阴离子，这些阴离子也具有控制反应性。 侧翼磷酸和NHC孤对电子的观众碳纤维在这些反应性位点提供动力学保护，从而使复合离子对的形成既包含一个反应性阳离子和阴离子。这些系统类似于传统沮丧的路易斯对（FLP），只是这些物种是静电束缚的。这样的物种可以实现更具挑战性的键激活/C-F键激活的组转移，例如CF4（一种有效的温室气体）的CF键键表明。此外，这些系统将提供独特的机会，以隔离FLP化学中所谓的难以捉摸的遭遇综合体。 这些系统将通过结晶离子对的固态氢化形成，并通过冷冻微电子衍射通过随后的分析进行研究。该项目的第二个实施方案是对配体对阴离子AU（I）水域催化剂的探索，并由Dianionic磷和NHC支持。这些过渡金属阴离子将与Trityl和辅助基离子配对，形成能够在金属的配位球中产生高反应性碳的试剂。 这种反应可能导致杂氧化添加和前所未有的低坐标烷基/芳基AU（III）化合物。靶向的AU（III）化合物将具有两个可访问的配位位点，因此可能能够进行经典的D8过渡金属催化。将探讨这些物种介导迁移插入，羰基化以及其他低坐标D8金属介导的其他反应的能力。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和知识分子的评估来支持的。更广泛的影响审查标准。

项目成果

Fusing 10-vertex closo -carborane anions with N-heterocyclic carbenes

将 10 顶点的近碳硼烷阴离子与 N-杂环卡宾稠合

• DOI: 10.1039/d2cc02596e
• 发表时间: 2022
• 期刊: Chemical Communications
• 影响因子: 4.9
• 作者: Tej Raviprolu, Varun;McArthur, Sarah E.;Banda, Isaac;Gregory, Aaron;McArthur, Scott G.;Fisher, Steven P.;Lavallo, Vincent
• 通讯作者: Lavallo, Vincent