Recognition primary ammonium ions

The same CIMS approach has been used for investigating the self-recognition processes in proton-bound tartrate trimers. The trimer chirality effect is consistent with the heterochiral trimers as more stable than the homochiral ones. The reverse is true when the proton in the proton-bound trimers is replaced by hydronium, ammonium ion, or primary aminium ions. " This changeover is... 

CyDs were coupled with calixarene or crown ether to improve their binding affinity. j8-CyD functionalized with diaza-18-crown-6 at the primary face 68 showed 7-10-fold greater affinities for aromatic ammonium ions [178] and the introduction of a benzo-18-crown-6 moiety at the secondary-hydroxy side 69 improved chiral recognition for tryptophan (Trp), whereas its introduction at the primary-hydroxy side 70 was not effective for the Trp recognition [179]. 

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