Dr. Zheng has returned from China, and indeed his return marks my return to the UA internship.
So far, we haven't heard a thing from Dr. Corrales, the computational chemist. Dr. Zheng brought it to my attention that I may be getting filed under spam due to my e-mail signature (which, if any of you haven't seen before, is depicted on the image in the right). Total spam-bait, right?
Anyway, we returned to the lab to find that the second compound that we wished to recrystallize, Eu(Tta)3, had not recrystallized a single bit. Despite the use of an antisolvent and despite the fact that we waited an entire week for it to recrystallize, the solution was far too diluted to allow the solute to manifest in solid form.
So,what was our solution to the problem? The "rotovap."
A rotovap is basically a giant vacuum connected to a boiler plate. The idea is that you heat up a liquid under a vacuum and rotate the solution at the same time. (You rotate the solution so that you can prevent the solution from boiling up into your vacuum and contaminating it -- for you see, you would not like this to happen.) You keep doing this such that the high vapor pressure of the solvent (which is higher than that of the solute) causes the solvent to be sucked up by the vacuum. In case you slept through Chemistry 101, all of this is another way to say that we're removing the amount of "diluting stuff" so that the solution becomes "less diluted" and "more concentrated." If the solution is "more concentrated," and we leave the solution to sit in a nice cool refrigerator for a while, then some solid material will emerge out of the "oversaturated solution." It's empirical fact, my friends.
That being said, it seems that time will be my best friend as I now wait for the recrystallization of Eu(Tta)3 to yield an adequate amount of product. From there, we will take the crystals from both compounds and finally react them with the missing key component -- called "TPTZ," which is responsible for replacing the remaining water ligands with nitrogen-based ligands that provide a higher quantum yield (ie higher photoluminescent efficiency, but that's for another blog post).
That's all for now, folks!
--Dany.
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