Azulene-Based BN-Heteroaromatics

Azulene, a nonalternant bicyclic
aromatic hydrocarbon, has unique
chemical and physical properties and is considered to be a promising
building block for constructing novel polycyclic aromatic hydrocarbons
(PAHs) and heteroaromatics. We present here the first two azulene-based
BN-heteroaromatics Az-BN-1 and Az-BN-2.
The chemical structures and optical and electrochemical properties
of both compounds have been investigated, as well as their sensing
behavior in response to fluoride ion. Az-BN-1 and Az-BN-2 show different photophysical properties from other
reported BN-embedded PAHs, such as lower band gaps and unusual fluorescence.
In addition, Az-BN-1 and Az-BN-2 exhibit
unexpected deboronization upon addition of trifluoroacetic acid, which
distinguishes them from other reported BN-heteroaromatics and can
be ascribed to the unique property of the azulene unit.