# Reaction of Blatter and Verdazyl Radicals with Arynes: Synthesis and Investigation of N‐Chiral, Antiaromatic Triazines, and Tetrazinones

## TL;DR

This study introduces a new chemical reaction using Blatter and verdazyl radicals with arynes to create antiaromatic and N-chiral triazines and tetrazinones with potential uses in materials science.

## Contribution

A novel radical annulation reaction of Blatter and verdazyl radicals with arynes is presented, enabling the synthesis of N-chiral and antiaromatic triazines and tetrazinones.

## Key findings

- N2-annulated triazines show distinct bending modes and retain antiaromaticity despite nonplanar geometries.
- N2-annulated triazines exhibit N-chirality and can be resolved into pure enantiomers with measurable N-inversion barriers.
- One triazine derivative shows intense fluorescence, and another shows long-term redox stability for battery applications.

## Abstract

Arynes are versatile building blocks in organic chemistry. In contrast to their extensively examined ionic reactivity, radical reactions with arynes remain scarcely explored. In this study, we present a novel radical annulation reaction of stable Blatter and verdazyl radicals with arynes, which offers access to polycyclic triazines and tetrazinones. The N2‐ and N4‐annulated triazines derived from Blatter radicals exhibit distinct bending modes of the 8π‐electron triazine ring, yet retain a certain degree of antiaromaticity despite their nonplanar geometries, as revealed by NICS and ACID calculations. Notably, the N2‐annulated triazines feature a strongly pyramidalized nitrogen atom with N‐chirality. Optical resolution yielded pure enantiomers, from which the configurational stability was assessed to determine the N‐inversion barrier. Furthermore, one of the N2‐annulated triazine derivatives displayed intense fluorescence, highlighting its potential as a scaffold for light‐emitting materials, whereas H‐cell cycling studies of the N4‐annulated triazine derivatives demonstrated long‐term stability of the redox process underscoring their utility for battery applications.

In this study a novel radical annulation reaction mode of Blatter and verdazyl radicals with arynes is demonstrated which offers access to antiaromatic and N‐chiral triazines and tetrazinones. The photophysical and electrochemical properties are investigated revealing their potential for application in materials science.