# Synthesis of Core‐Functionalised Naphthalenediimides from Naphthalenetetracarboxylic Dianhydride using a Vibratory Ball Mill: Bromination, Imidization and Heck‐Type Reactions

## TL;DR

A new method for making core-functionalized naphthalene diimides using mechanochemistry is faster and more sustainable than traditional methods.

## Contribution

A three-step mechanochemical synthesis of core-functionalized naphthalene diimides using a vibratory ball mill is introduced.

## Key findings

- Selective dibromination and diimidization were achieved in a vibratory ball mill for the first time.
- The synthesis of 2,6-dibromonaphthalenediimide (DBND) was completed in 5 hours, much faster than traditional methods.
- Heck-type reactions produced c-NDIs rapidly under ambient conditions without solvents or heating.

## Abstract

The synthesis of 9 core‐functionalised naphthalene diimide (c‐NDI) residues is reported via a 3‐step synthesis from naphthalenetetracarboxylic dianhydride using only mechanochemical activation. Selective dibromination and subsequent diimidization were achieved for the first time in a vibratory ball mill, resulting in the key structural intermediate, 2,6‐dibromonaphthalenediimide (DBND), which is the basis for elaboration into a multitude of organic electronic materials. Our new synthesis of DBND is achieved in just 5 hours reaction time over two steps compared to typical solution state times of 24 hours. Subsequent Heck‐type cross coupling reactions, with a range of styrene residues, produced a series of c‐NDIs in good yields. The Heck‐type reactions are rapid (1.5 hours), require no additional heating or solvent and are tolerant of atmospheric moisture and air.

Core‐functionalised naphthalene diimides (c‐NDIs) are an important component in organic electronics. Current methods for their production frequently require long reaction times, large quantities of solvent and inert conditions. Herein, we report the synthesis of a series c‐NDIs by a 3‐step synthesis from naphthalenetetracarboxylic dianhydride (NDI) using only environmentally sustainable mechanochemical methods and without excluding air or moisture.