Crystallization from Volatile Deep Eutectic Solvents

Abstract

A new class of deep eutectic solvents are presented which exhibit all of the physical characteristics of classical deep eutectic solvents, with the exception that one of the components is volatile when exposed to the atmosphere at room temperature. This enables a premeditated, autodestructive capability which can lead to novel crystalline identities. We demonstrate the effectiveness of this concept through the room-temperature crystallization of a broad range of organic molecules, with a particular focus on pharmaceuticals, that possess a variety of functional groups and molecular complexity. Furthermore, we show how, through the simple altering of the eutectic composition, polymorphism in paracetamol can be controlled, enabling the elusive metastable form II to spontaneously crystallize at room temperature.