Straus Art Lands on JACS Cover

By Wendy Plump
Wednesday, Aug. 19, 2020

Artwork created by the Department of Chemistry’s Daniel Straus, a postdoctoral research associate in the Cava Group, is featured on the cover of the Journal of the American Chemical Society (JACS) this week. The image supports the lab’s story, “Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4.”

“I was surprised when it was chosen, yes. But sometimes you have a project where it’s easy to tell a story with the picture,” said Straus. “This is probably the only project I’ve had where it’s relatively easy to tell a story with the picture.”

20200819 JACS Cover
The Aug. 19, 2020 cover of JACS features Daniel Straus’ depiction of how the molecules C60 and SnI4 self-assemble into macroscopic chiral crystals.
Illustration by Daniel Straus

The illustration depicts the chirality of the structure, formed from the self-assembly of two high-symmetry molecules, C60 and SnI4, by showing the counter-clockwise helical arrangement. Straus used the crystal structure he solved using X-ray diffraction to depict the structure using the program VESTA. Then, he used Photoshop to make it “look pretty.”

“Self-assembly is the process where you mix things together and then they form a structure. Normally in chemistry, you’ll form a bond between two things and you’ll link them chemically,” said Straus. “In self-assembly, the molecules arrange themselves into a crystal.”

A molecule is chiral when it cannot be superimposed on its mirror image. In Straus’ work, the molecules themselves are not chiral but, as his illustration shows, the crystals made from it are. This phenomenon has to do, he explained, with how the molecules self-assemble, or pack.

It is thought to be impossible to form a chiral structure from a mixture of two differently sized spherical components. The Cava lab paper shows that a mixture of tetrahedra and spheres can spontaneously generate chirality. These principles may be able to be applied to nanocrystals and engineered nanostructures.

“We think it’s the tetrahedral shape that is templating the chirality. And that’s … odd,” said Straus. “It was not previously known that tetrahedra could do that.”

Read the journal story here: