Picolinamide–Cu(Ac)2-imprinted polymer with high potential for recognition of picolinamide–copper acetate complex Original Research Article

In this report, with semi-empirical quantum method, we have studied the conformation and energy of supermolecule composed of picolinamide and its positional isomers with methacrylic acid. We tried to explore the reason why picolinamide was not likely to show imprinting effect when using methacrylic acid as functional monomer in our previous work. In order to produce imprinting effect, which was not achieved based on hydrogen bonding interaction, we have synthesized a molecular-imprinted polymer (MIP) based on copper ion coordination in prepolymerization. The complex in prepolymerization was composed of copper(II), acetate, picolinamide and 4-vinylpyridine (4-Vpy). Suprisingly, the MIP had high selectivity to picolinamide–copper acetate complex, and changes of either copper ion, picolinamide or acetate would result in decrease in the imprinting effect. This is also the first example where the high selective recognition of the MIP to its template was achieved mainly by inhibiting the binding of non-template rather than enhancing the binding of the template. And this report can be also looked upon as a first step towards the solution to the problem of imprinting of template that contains intramolecular hydrogen bond.