Design, Synthesis, and Reactivity of Diboryl- and Aminoboryl Carbenes

正在合成形式上碳上缺乏电子的卡宾类化合物。虽然大多数化合物的特征是碳原子形成四个化学键，但也有少数化合物的碳原子形成三个或更少的键。这种新的碳物种的隔离受到了这样一种信念的阻碍，即它们天生就不稳定。该项目将使用PI开发的方法来制备名为卡宾的化合物，这种化合物只包含两个碳键。在这个项目中，这些方法将扩展到以前未知的卡宾，其中碳原子与两个硼原子键合。这些物种的存在有可能增加我们对碳的化学反应如何发生的了解，从而允许控制含碳化合物的反应活性。最终，这些研究的结果有望通过提供更具选择性的合成方法来促进精细化学品和材料的制造。哈德诺教授的实验室参与了当地与高中的外联活动，这是一个儿童博物馆，将整个社区与本科生和研究生的研究联系起来。自20世纪60年代以来，单线态卡宾具有p2电子构型的想法一直被理论化，但到目前为止，这些物种在很大程度上没有在实验室中被孤立。利用首席研究员开发的合成方法，将制备二硼基卡宾(r2b-C-Br2)和相关的氨基硼基卡宾(R2N-C-Br2)。由于一些目标物种可能是不可隔离的，这项研究项目被视为高风险/高回报的努力。预测目标二硼基卡宾具有p2电子构型，这是在其他卡宾中没有观察到的构型。重要的是，这些卡宾被预测为在卡宾碳原子上非常亲电，并可能为新的卡宾反应提供机会。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

is synthesizing compounds of the carbenoid class that formally are electron deficient at carbon. While most compounds feature carbon atoms that form four chemical bonds, there are a handful in which carbons form three or fewer bonds. The isolation of such new carbon species has been impeded by the belief that they are inherently unstable. This project will use methods developed by the PI to prepare compounds called carbenes, which contain only two bonds to carbon. In this project, these methods will be extended to previously unknown carbenes where the carbon atom is bonded to two boron atoms. The availability of these species has the potential to add to our understanding of how chemical reactions of carbon take place, permitting control of the reactivity of carbon-containing compounds. Ultimately, results derived from these studies are expected to advance the manufacturing of fine chemicals and materials by providing more selective approaches to synthesis. Professor Hudnall's laboratory participates in local outreach activities with high schools, a children’s museum to connect the community at large with undergraduate and graduate research.The idea that singlet carbenes feature a p2 electronic configuration has been theorized since the 1960s, but thus far these species have largely eluded isolation in the laboratory. Utilizing synthetic methodologies developed by the principal investigator, diborylcarbenes (R2B-C-BR2) and the related aminoboryl carbenes (R2N-C-BR2) will be prepared. As some of the targeted species may be non-isolable, this research project is seen as a high risk/high reward effort. The targeted diborylcarbenes are predicted to have the p2 electron configuration, a configuration not observed in other carbenes. Importantly, these carbenes are predicted to be quite electrophilic at the carbene carbon atom and may provide opportunities for new manifolds of carbene reactivity.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.