Li Zhongshu, Hou Yuanfeng, Li Yaqi, Hinz Alexander, Chen Xiaodan
Lehn Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University, 510275, Guangzhou, P. R. China.
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Ox1 3TA, Oxford, UK.
Chemistry. 2018 Apr 3;24(19):4849-4855. doi: 10.1002/chem.201705403. Epub 2018 Feb 8.
Organic biradicals are usually very short lived species under standard laboratory conditions, which makes their experimental studies difficult. In contrast, heteroatom-substituted analogues of these biradicals show enhanced stability due to π-electron delocalization, which is why main group biradicals (or biradicaloids) of archetypical heterocyclobutanediyls have been thoroughly investigated. Herein, N-heterocyclic carbene (NHC)-stabilized dicarbondiphosphide compounds of the type (L )C P (L=NHC) were utilized to activate both single and multiple bonds in small molecules with a feasible concerted mechanism. This reactivity is explicable by considerable biradicaloid character of the dicarbondiphosphide compounds, which is further corroborated by theoretical studies. Furthermore, the dicarbondiphosphide compounds also exhibited Lewis base properties towards Lewis acids, such as borane and metal halides.
在标准实验室条件下，有机双自由基通常是寿命极短的物种，这使得对它们进行实验研究变得困难。相比之下，这些双自由基的杂原子取代类似物由于π电子离域而表现出增强的稳定性，这就是为什么典型的杂环丁二烯基主族双自由基（或类双自由基）得到了深入研究的原因。在此，利用（L）C₂P₂类型的N-杂环卡宾（NHC）稳定的二碳二磷化合物，通过可行的协同机制活化小分子中的单键和多键。这种反应活性可以通过二碳二磷化合物具有相当大的类双自由基特性来解释，理论研究进一步证实了这一点。此外，二碳二磷化合物对硼烷和金属卤化物等路易斯酸也表现出路易斯碱性质。
