"We like to make molecules that have no right to exist", says Dr David Mills from the University of Manchester.

"Imagining ways to make our target molecules is a fun and creative process, and provides satisfying challenges for us to overcome as synthetic chemists. We have chosen to focus on making lanthanide compounds as our knowledge of these elements lags behind most others in the Periodic Table.

"By putting these frontier elements in novel environments we hope to discover new phenomena that will become textbook material for future generations of scientists for a wide range of applied technologies."

Lanthanides are large metals with a variety of applications. They tend to form complexes by bonding to at least eight atoms. In their new paper, Dr Mills and his team have developed an unusual complex where the lanthanide is only bonded to two atoms. Moreover the complex adopts a bent conformation, rather than the more common linear shape.

They have achieved this by first synthesising a trigonal (three-membered) complex, with a halogen in the third spot. When they remove the halogen the bent structure of the other two ligands remains.

"By making such compounds with designer geometries we can maximise the fantastic magnetic and optical properties of the lanthanides", says Dr Mills.

"The unusual bent compounds that we have synthesized provide new insights into what makes the lanthanide elements tick. This knowledge can be transferred to hasten advances in the numerous real-world applications that lanthanides are currently employed, and to unlock future technologies such as the storage of magnetic data on individual molecules."

This article is free to read in our open access, flagship journal Chemical Science: David P. Mills et al., Chem. Sci., 2019, Advance Article. DOI: 10.1039/c9SC03431E. You can access our 2019 ChemSci Picks in this article collection.