UK scientists have engineered crystals with targeted properties using charge-assisted hydrogen bonding interactions.

The ability to design and build crystalline materials with properties precisely tailored to applications as diverse as catalysis, information storage and optical switches is a key aim in modern chemistry, according to Guy Orpen and colleagues at the University of Bristol.  These researchers say they might have come up with one way to do just that.

Orpen's team made a series of new crystal structures using the interaction between pyridinium cations and the dithiooxalate salts of various metals. The researchers say that in every case a hydrogen bond is formed between the dithiooxalate ligand and the nitrogen-hydrogen bond in the pyridinium cation.  The hydrogen bond forms reliably, even in the face of competition from other potential hydrogen bonding partners.

The reliability of this interaction means it can be used in the design of new crystals with predictable structures and properties.

Lee Brammer, a crystal engineering specialist at the University of Sheffield, UK, said Orpen's work is at the heart of crystal engineering where the deliberate design of functional crystalline materials is the goal.

There is still a lot to learn about the factors controlling crystal structure formation, and many new properties still to be discovered, said Orpen.

Tanya Smekal