| There are a lot of reasons to grow crystals | | | | polarity SLOWLY changes, the thermodynamic |
| in research, but none of them are more | | | | wonders of crystallization occur. In the case |
| important than the journal bump they cause. | | | | to the left, I've put some of my new |
| As it turns out, even collecting a crystal | | | | synthetic target, Tiklemaitaint A, into a |
| can be its own publication, albeit in a less | | | | vial filled with dichloromethane and I've |
| than interesting journal. Therefore, it is | | | | allowed pentane to slowly diffuse into it. If |
| with great efforts that we try to grow | | | | you look closely you'll see some pretty |
| crystals. | | | | crystals. |
| | | | |
| For those of us in the natural products game, | | | | Another method that's very popular is to |
| crystals all but remove the ambiguity with | | | | simply allow for slow diffusion. This method |
| any relative stereochemistry. This way, we | | | | is more straight forward. You simply layer |
| only have two possible molecules to make. | | | | one solvent on top of another and the slow |
| SURE, you can say you've made heptacene and | | | | diffusion process causes crystals to form in |
| stabilized it by various things, but you're | | | | the middle. So, that's pretty easy. Then |
| assured a JACS or Angew paper if you can give | | | | again, the easiest way is to just keep some |
| 'em a cif file. And since blogs are useless | | | | of your crap in an NMR tube and forget about |
| (imho) if they fail to inform, I'll show you | | | | it and then one day look over and discover |
| how 'ol Kyle grows up his crystals. | | | | amazing crystals. That's possibly the best |
| | | | way to do it, since there's no effort and |
| I do my own data collection at our world | | | | it's always a surprise. |
| famous crystal structure facility, mount my | | | | |
| own crystals, solve my own diffractions and | | | | You can also cap your NMR tube (or any vial, |
| whatnot, so I've vested a lot of interest in | | | | really) and drop it into a (really good) |
| this sort of stuff. That isn't to say I'm an | | | | dewar with some hot solvent. Cap that baby |
| expert, of course. Now, all I do is organic | | | | tight and put it in the freezer. Hopefully, |
| crystals that aren't air or moisture | | | | it will take a few days for the solvent to |
| sensitive. So this isn't an exhaustive review | | | | get down to zero, at which point you can |
| by any means. For a more in depth guide, I | | | | extract your vial and MAYBE see some |
| suggest you look at this. | | | | crystals. If you're lucky enough to work |
| | | | where there is a -72 chill room (or -20 or |
| First thing I usually try is to do a | | | | -50) (a deep freezer works too, if you have |
| vial-in-vial vapor diffusion. This is a | | | | the space) where you can just plop it in. (If |
| simple little ditty in which one places their | | | | it's owned by the asshole biochemists, tell |
| compound inside of a small vial in a solvent | | | | them it's DI/DI sugar water. It's alright to |
| it is reasonably soluble in and putting it in | | | | lie to biochemists. They'll believe anything |
| a larger vial filled with volatile solvent | | | | if you tell them entropy made you do it.) |
| that it is not soluble in at all. Overtime | | | | I've never tried to make crystals at the low |
| the volatile solvent will evaporate up and | | | | temperature. I can't imagine mounting them |
| into the less volatile solvent and slowly | | | | would be that fun. |
| dissolve and diffuse in there. As the | | | | |