Details

Autor(en) / Beteiligte

• Deng, Weikang
• Liu, Yang
• Shimizu, Daiki
• Tanaka, Takayuki
• Nakai, Akito
• Rao, Yutao
• Xu, Ling
• Zhou, Mingbo
• Osuka, Atsuhiro
• Song, Jianxin

Titel

Facile Formation of Stable Neutral Radicals and Cations from [22]Smaragdyrin BF 2 Complexes

Ist Teil von

• Chemistry : a European journal, 2023-02, Vol.29 (11), p.e202203484

Ort / Verlag

Germany

Erscheinungsjahr

2023

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• meso-Trimesityl-substituted [20]smaragdyrin freebase was synthesized by p-toluenesulfonic acid catalyzed reaction of 5-mesityldipyrromethane and 2,14-dibromodipyrrin in an improved yield of 63 %. Unexpectedly, treatment of the [20]smaragdyrin freebase with BF  ⋅ OEt and triethylamine (TEA) gave a stable radical species, in which the BF unit is coordinated at the tripyrrin site, probably by ready release of a hydrogen atom of a [22]smaragdyrin BF complex. Similar treatment of [22]smaragdyrin free base produced another [22]smaragdyrin BF complex, in which the BF unit is coordinated at the dipyrrin site. The tripyrrin site coordinated neutral radical was oxidized with AgSbF to give a stable antiaromatic cation; this was reduced with NaBH to its 22π congener, which was easily oxidized back to the neutral radical in the air and rearranged to thermodynamically stable dipyrrin site coordinated [22]smaragdyrin BF complex upon treatment with BF  ⋅ OEt and TEA. Further, the dipyrrin site coordinated [22]smaragdyrin BF complex was similarly oxidized to a stable neutral radical and a stable cation in a stepwise manner. This work demonstrates a rare ability of smaragdyrin BF complexes to exist in multiple redox states, particularly forming a stable neutral radical by facile release of a hydrogen atom.