Boronic acids combination with other interactions

Boronic Acids in Combination with other Interactions. 

Boronic acid binding sites can also be used in combination with other covalent or noncovalent interactions. Glyceric acid and derivatives were thus bound as boronic esters aided by electrostatic, hydrophobic, charge-transfer interactions, or hydrogen bonding [39]. A boronic ester bond and a Schiflf base have been used for the imprinting of D-glyceraldehyde [4] and of l-DOPA in 8 [48]. 

Simultaneous, multiple ester formation was employed to assemble larger multitopic assemblies. For example, self-assembled molecular capsules via boronate esterification have been demonstrated. Two calix[3]arenes, one having the upper rim functionalized with diols, the other functionalized with boronic acids, were combined in the presence of a templating agent to form the heterodimeric capsule (Fig. 25). Extensive NMR analysis was performed to show that the two calixarenes in solution by themselves do not interact. It is only when tetramethyl ammonium acetate is added that the capsule forms. NMR diffusion studies have further demonstrated that the ammonium cation is included within the cavity. In addition, reversible decomposition-reconstruction of the capsule was observed in response to pH. 

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