[kidd0223]

Hello all,

I've just made ionic compound of some sort of imidazolium salt with iodide counterion.  On TLC it's really polar and doesn't go up well on TLC plate even in DCM/acetone mixture solvents.  Unfortunately I also have 2 impurities present and was wondering what would be the best way to separate them.  Will it be okay to try Prep. scale TLC and/or regular column chromatography with ionic compound in general? 

Also after purification of this compound, I need to do ion exchange reaction to exchange iodine ion to tetrafluoroborate.  What would be the best way to characterize once this ion exchange reaction has come to completion and give the product with tetrafluoroborate anion.  Any help/comment will be highly appreciated.  Thank you guys. 

[Cesium-137]

As far as separating very polar compounds (in general) try reversed phase C18 silica on a column. Eluting with H20 should pull off your ionic compound. If you try regular phase chromatography I would guess the compound would never come off... Especially if it has carboxylic acid functionality. Try spotting on reverse phase plates to see how your compound will act on reverse phase gel before putting it on your column!! Depending on the impurities, size exclusion might work on LH20 sephadex. I've heard of bio-chemists using ion exchange chromatography for purifying very polar or ionic compounds but I have never tried it and am too unfamiliar with the technique to lend advice there.