摘要:
The selective mono-alkylation of a calix[4]arene with a functionalized benzaldehyde followed by the condensation with dipyrrylmethane afforded in good yield a porphyrin substituted by two calix[4]arenes. The same multisite ligand was alternatively obtained by double monoalkylation of two calix[4]arenes with a functionalized porphyrin. The two calixarene units are in cone shape and thus can accomodate neutral organic guests. The efficiency of the fluorescence quenching of two porphyrins by benzoquinone has been evaluated and compared. In a first approximation, Stern-Volmer plots provide evidence for an enhanced quenching when calixarene hosts are bound to the porphyrin.