Molecules: You'd better learn to live with them.
Benzophenone is something you probably encounter most often in sunscreen:
It looks like it should be a profoundly fluorescent molecule to the semi-initiated, but for quantum-mechanical reasons, it is instead a phosphorescent molecule and won't emit much at all at room temperature.. If you cool it down to liquid nitrogen temperatures you can see emission from the "triplet state."
You can also make a great solution-phase drying reagent from it - benzophenone ketyl. It's one of the neater things in an organic lab - a boiling purple solution giving you clear, pure, dry solvent.
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Comments
I tried to synthesize this from benzene, benzyl chloride, and aluminum trichloride utilizing a Friedel-Crafts reaction in high school. The end product formed was a deep blue colour. That surprised me. Apparently it was a reaction of the benzophenone with the metallic sodium we used as a drying agent. Back in the 70's, high school kids could do this stuff.
Posted by: Dave S. | September 21, 2007 10:33 PM
Was there Na in your rxn mixture? I would expect it'd hit the acyl chloride first of all. Or Al(III).
Posted by: Molecule of the Day | September 21, 2007 11:08 PM
I think it was some point later on, after the reaction itself. Suffice to say that was 30 years ago, so I may be mixing memories of totally different experiments! Kids, don't try that at home.
I do recall the teacher saying it had something to do with sodium though. We lived by the sea...could have meant salt from the atmosphere?
Posted by: Dave S. | September 22, 2007 8:57 AM
Benzophenone is great stuff! High-boiling eutectic with diphenyl ether. The very best is cooking it up with added gaseous H2S and HCl in solvent to make extraordinarily blue Ph2C=S. Then M(CO)6 (M= W,Mo,Cr) and UV light in solvent to make profoundly royal purple (Ph2C=S)M(CO)5.
Can one dope a polymerization with both to get pale blue acrylic, etc., sheet that light exposes to deep purple and thermally reverts?
Posted by: Uncle Al | September 22, 2007 12:28 PM