Steric Shielding vs Structural Constraint in a Boron-Containing Polycyclic Aromatic Hydrocarbon
Steric Shielding vs Structural Constraint in a Boron-Containing Polycyclic Aromatic Hydrocarbon
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DOI：
10.1021/acs.organomet.6b00800
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发表时间：
2017-07-24
期刊：
影响因子：
2.8
通讯作者：
Wagner, Matthias
中科院分区：
文献类型：
--
作者：
Hertz, Valentin M.;Ando, Naoki;Wagner, Matthias
The highly reactive boron-doped polycyclic aromatic hydrocarbon 8H-8-bromo-8-borabenzo[gh]tetraphene has been synthesized via a multistep sequence encompassing a Peterson olefination, a stilbene-type photocyclization, and an Si/B exchange reaction. The compound was subsequently treated with mesityllithium to give the derivative 3 or with [2,6-bis(propen-2-yl)phenyl]lithium to furnish the intermediate 4. A scandium(III) triflate mediated Friedel Crafts reaction transformed 4 into the rigid, planarized triarylborane 5. Compounds 3 and 5 are both inert toward air and moisture but are still able to bind fluoride ions, where the affinity of 3 in CHCl3 is higher than that of 5. Both arylboranes are yellow solids, and their solutions exhibit an intense blue fluorescence (Phi(PL) = 85% (3), 89% (5)). According to cyclic voltammetry, reversible reduction occurs at half-wave potentials of E-1/2 = -2.05 V (3) and 2.14 V (5; in THF, vs FcH/FcH(+)). The crystal lattices consist of pi-stacked dimers, arranged in herringbone patterns. Importantly, 3 and 5 share nearly identical properties, despite possessing fundamentally different structures.
