Library of Azabenz-Annulated Core-Extended Perylene Derivatives with Diverse Substitution Patterns and Tunable Electronic and Optical Properties

Here,
we present a collection of different azabenz-annulated perylene
derivatives. By developing new synthetic strategies and improving
existing protocols, we have expanded the structural diversity of these
dye molecules to a multifunctional class of ligating chromophores.
The Pictet–Spengler (PS) reaction of 1-amino-perylenes with
different aldehydes is used to modify the terminal substitution pattern.
PS transformations of 1,6- and/or 1,7-diamino perylenes result in
2-fold annulated nitrogen-containing coronene-type molecules like anti-(ab)2-PBI 15, syn-(ab)2-PBI 16, and syn-(ab)2-PTE 18. In addition, azabenz-annulated perylene
bisanhydrides (ab-PBA 6 and syn-(ab)2-PBA 19) were explored as universal starting
materials providing access to any desired imide functionality. Furthermore,
a newly developed regioselective nitration procedure for perylene
monoimide diesters (PMIDE) enables the synthesis of 1-nitro-PMIDE 10 and thus of azabenz-annulated perylene derivatives with
unsymmetric peri-substitution patterns (ab-PMIDE 12 and ab-PMIMA 13). According to our spectroscopic
and theoretical investigations, the optical and electrochemical properties
of these multifunctional chromophores can easily be modified and adjusted
to many desirable applications following the synthetic strategies
presented in this work.