Lin Yu-Jiang, Liu Wei-Chun, Liu Yi-Hung, Lee Gene-Hsiang, Chien Su-Ying, Chiu Ching-Wen
Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan.
Nat Commun. 2022 Nov 17;13(1):7051. doi: 10.1038/s41467-022-34900-7.
The pursuit of di-coordinate boron radical has been continued for more than a half century, and their stabilization and structural characterization remains a challenge. Here we report the isolation and structural characterization of a linear di-coordinate boron radical cation, achieved by stabilizing the two reactive atomic orbitals of the central boron atom by two orthogonal π-donating and π-accepting functionalities. The electron deficient radical cation undergoes facile one-electron reduction to borylene and binds Lewis base to give heteroleptic tri-coordinate boron radical cation. The co-existence of half-filled and empty p orbitals at boron also allows the CO-regulated electron transfer to be explored. As the introduction of CO promotes the electron transfer from a tri-coordinate neutral boron radical to a boron radical cation, the removal of CO under vacuum furnishes the reverse electron transfer from borylene to yield a solution consisting of two boron radicals.
对双配位硼自由基的研究已经持续了半个多世纪，但其稳定化和结构表征仍然是一个挑战。在此，我们报告了一种线性双配位硼自由基阳离子的分离和结构表征，该阳离子通过两个正交的π供体和π受体官能团稳定中心硼原子的两个活性原子轨道而实现。缺电子的自由基阳离子易于进行单电子还原生成硼烯，并与路易斯碱结合生成杂配三配位硼自由基阳离子。硼原子上半充满和空的p轨道共存，也使得可以探索CO调控的电子转移。由于引入CO促进了电子从三配位中性硼自由基转移到硼自由基阳离子，在真空下去除CO则提供了从硼烯的反向电子转移，从而产生由两个硼自由基组成的溶液。
