Three-Sided Pyramids Form 2D Structures

While doing a routine check on a batch of tiny gold tetrahedrons, Rice chemist Matthew Jones and graduate student Zhihua Cheng found their microscopic particles had the unanticipated ability to arrange themselves into 2D chiral superstructures  current science daily.

The discovery, which is detailed in a new study in Nature Communications, is likely the first-known spontaneous self-assembly of a planar chiral structure, Jones said.

Chiral structures are mirror opposites, similar forms, like right and left hands, that can’t be superimposed on one another. It’s an important distinction in drug design, where chiral molecules may be therapeutic in one handedness and toxic in the other.

Tetrahedrons themselves are not chiral — that is, they can be superimposed on their mirror images. That made it doubly surprising that they fell so easily into chiral forms during experiments when evaporated onto a surface, Jones said.

“This is unexpected,” he said. “It’s very rare to see a chiral structure form when your building blocks are not chiral.”