# Twisted 1‐ and 2‐Azaperopyrenes: Synthesis, Structure, and Properties

## TL;DR

Scientists synthesized new twisted nitrogen-containing peropyrenes and studied their structure and properties using various methods.

## Contribution

The novel synthesis of twisted 1- and 2-azaperopyrenes and their unique conformational isomorphism are newly reported.

## Key findings

- Twisted conformations of azaperopyrenes were confirmed with twist angles of 10.0–19.9° and 5.5–25.0°.
- Regioselective N-doping affects photophysical and electrochemical properties compared to carbon analogs.

## Abstract

A synthesis of hitherto unknown 1‐ and 2‐azaperopyrenes, twisted nitrogen‐doped peropyrenes, is reported. The synthesis is based on a Brønsted acid‐mediated benzannulation of alkynes. Key alkyne intermediates are synthesized via two complementary routes, including a Pd/C‐catalyzed, copper‐ and amine‐free Sonogashira‐type coupling of (hetero)aryl chlorides, enabling access to both carbo‐ and heteroatom‐substituted peropyrene frameworks. X‐ray crystallography reveals twisted conformations with bay and end‐to‐end twist angles ranging between 10.0–19.9° and 5.5–25.0°, respectively, as well as unprecedented conformational isomorphism. The influence of regioselective single N‐doping within the twisted peropyrene framework on the photophysical and electrochemical properties were elucidated by combined experimental and computational studies and compared with those of the carbon congener.