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Chemistry In Pictures

Chemistry in Pictures: Shape-shifter in pink

by Manny I. Fox Morone
July 2, 2020

A shiny purple powder sits in the fold of a piece of filter paper that has a large hot-pink stain emanating from its center.
Credit: Sean Connolly
A reaction scheme showing a conjugated organic molecule cyclizing when treated with light and made linear again when treated with heat.
Credit: Sean Connolly

After filtering his product, Sean Connolly posted this colorful design on Instagram after it seeped into his filter paper. The compound he’d synthesized is a type of molecule called a donor-acceptor Stenhouse adduct (DASA), a type of molecule that can interact with light. DASAs have the ability to switch between a longer, linear form—which is what Connolly synthesized here—and a more compact cyclized form when exposed to light or heat. The reaction scheme shows an example of that process for Connolly’s molecule. Scientists hope to harness this kind of molecular shape transformation by putting photoswitches like this one into shape-shifting materials that can be controlled by light.

Submitted by Sean Connolly via Instagram. Follow Sean on Instagram @chemistry_bro.

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