If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Chemistry In Pictures

Chemistry in Pictures: Chemical smile

by Alexandra Taylor
April 25, 2018

Credit: Michel Rickhaus and Andrew Frawley

Michel Rickhaus and Andrew Frawley at the University of Oxford drew a smiley face in a solution of a special dye using an everyday laser pointer. The dye consisted of a fluorescent molecule attached to spironaphthoxazine, which changes its structure from a closed one to an open conformation when exposed to blue light—405 nm, to be exact. “By coupling this spironaphthoxazine to a fluorescent dye, we can reversibly switch the dye off and on,” Rickhaus explains, with the dye going from yellow in the closed form to purple in the open. After about 30 seconds, the molecule reverts to yellow, and the smiley gradually disappears. The two chemists’ lab is examining such photoswitchable dyes for use in superresolution microscopy. “The video came about as a bit of fun during my synthesis—hence the smiley. But we do use the laser pointer in the purification process,” he says. The laser allows them to quickly check that what they’ve purified contains the correct product.

Credit: Michel Rickhaus and Andrew Frawley

Do science. Take pictures. Win money. Enter our photo contest here.

Related C&EN Content:

How Thiols Photoswitch Cyanine Dyes

Photoswitchable drugs could light the way to more targeted treatments

Dye Colors Up Live Cell Surfaces In 3-D.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.