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Chemistry In Pictures

Chemistry in Pictures: Fluorescent foam

by Manny I. Fox Morone
September 15, 2020


A series of three images showing a flask full of a foamy chemical, and under visible light the foam looks white, but under two different ultraviolet light wavelengths the same flask glows blue and cyan.
Credit: Priya Ranjan Sahoo

After drying the liquid in his flask under high vacuum, Priya Ranjan Sahoo saw this foam start to bubble up and fill the vessel. Oddly, this netlike foam glowed under ultraviolet light because his product was a silicon rhodamine molecule. Sahoo, a postdoc at Tohoku University’s Institute of Multidisciplinary Research for Advanced Materials, aims to use silicon rhodamines as switchable fluorescent probes in imaging experiments. The key to switchability is controlling which form the molecule takes: when its five-membered lactone ring is intact, the molecule shows very little fluorescence, but when the lactone pops open (transformation shown in scheme), it exhibits an eerie blue glow under a variety of ultraviolet wavelengths (center and right photo; visible light shown in left photo).

A reaction scheme showing the lactone ring of a silicon rhodamine popping open and unmasking its fluorescent glow.
Credit: Priya Ranjan Sahoo

Submitted by Priya Ranjan Sahoo

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This story was updated on Oct. 1, 2020, to correct description of the left and right photos. Those descriptions were originally reversed.


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