Face-to-face porphyrin moieties assembled with spacing for pyrazine recognition in molecularly imprinted polymers.

A strategy for arranging two porphyrin moieties in a face-to-face fashion in polymeric material was demonstrated by molecular imprinting, whereby porphyrin Zn(II) complex monomers were cross-linked with ethylene glycol dimethacrylate in the presence of pyrazine or 1,5-naphthyridine as a template molecule. In chromatographic studies using the resultant imprinted polymers as stationary phase, both the polymers showed selectivity for the original template molecule, suggesting that two zinc porphyrin moieties were immobilized in the face-to-face fashion, and were center-aligned for pyrazine recognition and offset-arranged for 1,5-naphthyridine recognition. The imprinted polymer with porphyrin moieties also showed a decrease in its fluorescence intensity in response to the concentration of the target molecule, suggesting the potential utility as sensing material.