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Chemistry In Pictures

Chemistry in Pictures: A spooky separation

by Manny Morone
October 29, 2019


Credit: Jon Grimm

In this eerie and (unintentionally) Halloween-themed edition of Chemistry in Pictures, Jon Grimm used a UV light, a time-lapse camera, and a silica column to purify a fluorescent dye that he helped develop at Howard Hughes Medical Institute’s Janelia Research Campus in the lab of Luke Lavis. One of the steps in synthesizing these dyes involves adding an amine (azetidine in this reaction, shown above) to the dye’s carbon scaffold using a palladium-catalyzed reaction. It’s the product of that reaction that Grimm was running through this silica column. The hallmark of the unusually bright so-called Janelia Fluor dyes is the straightforward pathway for changing the color that these molecules emit when they glow. By swapping out the azetidine for a different amine or swapping one of the oxygen atoms for a silicon, the color that the dyes fluoresce can be predictably fine-tuned, which makes the rainbow of Janelia Fluor dyes useful in complex imaging experiments in which many distinct fluorescent markers are needed.

A dibromofluoran gets coupled to two azetidine molecules to form an aminated rhodamine, or Janelia Fluor dye, molecule.

Submitted by Jon Grimm. Follow Grimm on Instagram (@dyerfulchymist) and Twitter (@jonathangrimm).

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Related C&EN Content:

Meet the Janelia chemist crafting glowing molecular tools for neuroscientists

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Chemistry in Pictures: Fluorescence unmasked.



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