Amsterdam produces first in new class of materials

Research lead

Researchers at Amsterdam University have succeeded in making the first-ever piece of chiral palladium metal, a feat they say will lead to an entirely new class of materials. These are metallo-organics, combining the variety of organic molecules with the special properties of metals.

Palladium metal is induced to adopt chiral forms by using organic template molecules, which are later removed. This is significant because metals do not normally possess the property of chirality, which means that molecules have mirror-image, or left and right-handed forms.

These new materials, metallo-organics, are the opposite of organometallics. The researchers say the possibilities raised by the ability to imprint metals with organic molecules are practically endless.

Using simple precipitation technology, Gadi Rothenberg and Laura Duran Pachon imprinted palladium metal crystals with a chiral organic template. The entire template was then removed, leaving a chiral cavity in the palladium metal. The metal itself retains all its usual properties, such as malleability, conductivity, and catalytic activity. To demonstrate this, the researchers even pressed a chiral palladium coin, roughly the size of a two-cent piece.

The chirality of the metal was proven in various experiments carried out in collaboration with researchers at the Weizmann Institute of Science in Rehovot, Israel. Like all metals, palladium exhibits the photo-electric effect: when a high-energy photon hits the metal, an electron is ejected. However, the Rehovot group showed that the palladium coin made in Amsterdam ejected different electrons when exposed to clockwise polarised or anticlockwise polarised photons, proving the metal’s chirality.

Another experiment demonstrated differences in absorption reactions in the two chiral metals.