Abstract
Herein we report a palladium-catalyzed annulation
reaction consisting of a Suzuki–Miyaura cross-coupling and a
C-H arylation cascade for the synthesis of tetrachlorinated
polycyclic aromatic dicarboximides (PADIs). This convergent
synthetic route afforded a broad series of hitherto unknown
electron-deficient PADIs under optimized reaction conditions
by coupling of a dibromo-tetrachloro-perylene dicarboximide
with different polycyclic aromatic hydrocarbon (PAH)
boronic acid pinacol esters in up to 89% yields. The new
PADI compounds show broad absorption in the visible
range and some of them emit in the near-infrared (NIR)
region. Cyclic and square wave voltammetric studies revealed
that these tetrachlorinated PADIs are more electrondeficient
than a non-chlorinated reference compound and
they possess lower lying frontier orbitals. Thus, the newly
synthesized electron-poor PADIs are potential n-type semiconductors.
Moreover, these chlorinated PADIs are interesting
building blocks for the construction of large p-extended
arrays by metal-mediated coupling reactions.
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