A novel complex of an alkali metal and a 5f-rare earth element has been made by French chemists.

Oxalic amidino complexes of transition metals have steric and electronic properties that can be modified through their nitrogen substituents, making them particularly desirable for use as catalysts of olefin polymerisation reactions.

Claude Villiers, Michel Ephritikhine and their team at the DRECAM institute developed a reductive coupling technique using metallic lithium to produce the organometallic dianions. These are then easily converted to the final complexes.

Using this route, the researchers produced an oxalamidino complex of an alkali metal and uranium. This is the first example of such a complex with a 5f-rare earth element.

'This novel synthetic route is widely applicable to a variety of metal ions and is particularly attractive for those which are in their highest oxidation state or which are too stable to be easily oxidised,' said Ephritikhine.

Sophia Anderton