Hi everyone, I have synthesized 3-amino functionalized cage molecule by treating the benzophenoneimine bonded cage with excess aqueous HCl. The identity of the molecule was confirmed by NMR spectroscopy but I am now suspicious from the fact that amine groups can be in the form of -NH3Cl or just -NH2 because I could not achieve to crystallize the same molecule reported in the literature. Do you have any idea about how to distinguish whether the amino groups are in its protonated form or not.
Best regards.
you have to prepare titration curve for your molecule also you have to measure PKa of your molecule
try to use qualitative test like use Silver nitrate to check the presence of chloride anion
Der Ferit,
if you have a a-protic solvent (with narrow enough NMR signal of the NH2/NH3+) you should be able to discriminate this by the integral of the signal. Optionally you may want to use a multiplicity edited (or along f1 undecoupled/refocussed) version of 1H/15N HSQC - if you have enough material!
Good luck
Alfred
If the compound is water soluble - aminogroup is protonated. If it is not water soluble - aminogroup is free. More, the water solution must be alkaline in the presence of free aminogroup.
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