Wednesday, February 13, 2019

Blue Shit, Bronze Shit

Over the last few years at work, I've been working with fluorescent dyes. Specifically I've been connecting them to an Hsp90 protein binding ligand to make a compound which, for whatever reason, selectively goes into cancer cells versus normal cells. Anyhow, to make these things, I sometimes have to make the dye which I couple to a ligand-linker construct via a Suzuki coupling. But that's not what this is about. This is about a weird property of these dyes. I've used one dye extensively because it absorbs and emits in a region compatible with widely available instrumentation. Recently, my supply has been running low and so I've been making more. The really cool thing about these dyes is that they start out deeply colored, in this case blue. But when they are purified and concentrated, they form a solid with a very metallic sheen. You can even see yourself in the reflection. Very weird. Of course I have some pictures. Here's the dye:


And here's how it looks when you make a bunch (7 g) of it.
Starts out Deep Blue.


Turns to Bronze.



This is pretty strange considering this molecule only contains carbon, hydrogen, nitrogen, oxygen and sulfur.

For the nerds reading this, here's the spectra of a compound after the conjugation. I don't have one of the dye itself, though it should be very close.