# Sublimation aides and abets co-milling and discoloration involving quinhydrone

## TL;DR

This paper explores how co-milling and sublimation affect the structure and color of quinhydrone when combined with specific additives.

## Contribution

The study reveals sublimation aids in forming new cocrystals during co-milling of quinhydrone.

## Key findings

- Co-milling with 4,4′-BPE or 4-MA causes discoloration of quinhydrone.
- Sublimation of BZQ leads to the formation of new cocrystals (HQ)·(4,4′-BPE) and (HQ)·2(4-MA).

## Abstract

We report an application of co-milling to the binary cocrystal (BZQ)·(HQ) or commonly known as quinhydrone. The co-milling is performed with either trans-bis(4-pyridyl)ethylene (4.4′-BPE) or 4-methoxyaniline (4-MA). In both cases, the dark green color of (BZQ)·(HQ) in the sample undergoes discoloration with the co-milling. Sublimation of BZQ occurs with dismantling of (BZQ)·(HQ) to allow for formation of the targeted cocrystals (HQ)·(4,4′-BPE) and (HQ)·2(4-MA).