A B−B Bond-Containing Polycyclic π-Electron System: Dithieno-1,2-dihydro-1,2-diborin and Its Dianion
摘要:
As a B-B bond-containing polycyclic pi-electron system, a dithieno[3,2-c:2',3'-e](1,2-dihydro-1,2-diborin) derivative and its dianion salts were successfully prepared, and their structures were determined by X-ray crystallography. The neutral. dithieno-1,2dihydro-1,2-diborin has a twisted diborin ring in which both the sigma-TT and p-pi* orbital interactions between the bithiophene pi framework and the B-B bond moiety effectively take place, giving rise to an absorption that is significantly red-shifted compared with that of the parent bithiophene. Upon a two-electron reduction, the dithienodiborin pi framework becomes planar and has a characteristic peripheral. pi conjugation through the B-B bond with 14 pi etectrons. Furthermore, the dianion salts show an intriguing countercation effect on their photophysical, properties, indicative of possible etectronic tuning by the countercations.
A B−B Bond-Containing Polycyclic π-Electron System: Dithieno-1,2-dihydro-1,2-diborin and Its Dianion
摘要:
As a B-B bond-containing polycyclic pi-electron system, a dithieno[3,2-c:2',3'-e](1,2-dihydro-1,2-diborin) derivative and its dianion salts were successfully prepared, and their structures were determined by X-ray crystallography. The neutral. dithieno-1,2dihydro-1,2-diborin has a twisted diborin ring in which both the sigma-TT and p-pi* orbital interactions between the bithiophene pi framework and the B-B bond moiety effectively take place, giving rise to an absorption that is significantly red-shifted compared with that of the parent bithiophene. Upon a two-electron reduction, the dithienodiborin pi framework becomes planar and has a characteristic peripheral. pi conjugation through the B-B bond with 14 pi etectrons. Furthermore, the dianion salts show an intriguing countercation effect on their photophysical, properties, indicative of possible etectronic tuning by the countercations.
作者:Takafumi Araki、Masato Hirai、Atsushi Wakamiya、Warren E. Piers、Shigehiro Yamaguchi
DOI:10.1246/cl.170812
日期:2017.12.5
B,B-Dimesityl-substituted dithieno-1,2-dihydro-1,2-diborin was synthesized and its properties and reactivity were studied. Owing to the noticeably electron-deficient and antiaromatic character of the 1,2-dihydro-1,2-diborin ring, this compound was found to homolytically cleave diatomic hydrogen (H2) gas at ambient temperature under 1 atm to afford a hydrogen-bridged bis(borane). This reaction was accompanied by a dramatic color change from dark green to yellow in addition to a turn-on fluorescence response.
As a B-B bond-containing polycyclic pi-electron system, a dithieno[3,2-c:2',3'-e](1,2-dihydro-1,2-diborin) derivative and its dianion salts were successfully prepared, and their structures were determined by X-ray crystallography. The neutral. dithieno-1,2dihydro-1,2-diborin has a twisted diborin ring in which both the sigma-TT and p-pi* orbital interactions between the bithiophene pi framework and the B-B bond moiety effectively take place, giving rise to an absorption that is significantly red-shifted compared with that of the parent bithiophene. Upon a two-electron reduction, the dithienodiborin pi framework becomes planar and has a characteristic peripheral. pi conjugation through the B-B bond with 14 pi etectrons. Furthermore, the dianion salts show an intriguing countercation effect on their photophysical, properties, indicative of possible etectronic tuning by the countercations.