An Air-Stable Organoboron Compound, Dithienooxadiborepine: Preparation and Functionalization

作者：Yan, Qifan^*; Yin, Mengxuan; Chen, Cheng; Zhang, Yuankun

来源：Journal of Organic Chemistry, 2018, 83(16): 9096-9102.

DOI：10.1021/acs.joc.8b01188

• PI-ELECTRON SYSTEMS
• POLYCYCLIC AROMATICS
• CONJUGATED POLYMERS
• OPTICAL-PROPERTIES
• CHARGE-TRANSPORT
• BORON
• THIOPHENE
• SEMICONDUCTORS
• DIBENZOBOROLE
• DEFICIENT

pi-Conjugated organoboron molecules, which are easy to prepare, stable against moisture, and easy to functionalize, are scarce. Here, we report a one-pot synthesis of an air-stable organoboron compound, dithienooxadiborepine 1 in 17% yield on a 600 mg scale without separation or handling an air-sensitive intermediate. Dithienooxadiborepine 1 showed excellent stability under ambient conditions, allowing conventional column chromatography purification. Functionalization of 1 was realized via direct bromination using NBS and further Stille coupling reactions, giving access to longer pi-conjugated molecules SA and SB. Single-crystal structures of compounds 4, 5A, and 5B not only unambiguously verified the chemical identity of dithienooxadiborepine 1 but also revealed that both the seven-member oxadiborepine ring and the 5-7-5 fused dithienooxadiborepine ring system are planar. UV-vis absorption and fluorescence emission measurements of SA and 5B showed bathochromic shifted absorption and emission relative to 1, evidencing good pi-conjugation. Cyclic voltammograms of SA and SB displayed two reduction peaks corresponding to two electron-accepting events at two boron atoms. These results proved dithienooxadiborepine 1 a potent pi-conjugating building block for electron-accepting materials.

• 出版日期2018-8-17
• 单位华东理工大学