Triazole‐bearing oligo(ethylene glycol)‐strapped zinc porphyrins as dual mode ion‐binding receptors

A series of triazole‐bearing oligo(ethylene glycol)‐strapped zinc porphyrins ( P Zn 4EG and P Zn 5EG ) have been prepared as artificial ion‐binding receptors. Both P Zn 4EG and P Zn 5EG exhibit UV/Vis absorption changes in a solvent‐dependent manner upon titration with halides and alkali metal ions. In tetrahydrofuran, both P Zn 4EG and P Zn 5EG exhibit spectral shifts upon the addition of halide ions through axial coordination, whereas the absorption does not change upon the addition of alkali metal ions. On the other hand, in 10% MeCN/CHCl 3 , the UV/Vis absorption spectra of both P Zn 4EG and P Zn 5EG do not change upon the addition of an excess amount of halide ions; however, P Zn 4EG and P Zn 5EG show selective alkali metal ion‐binding properties in this solvent. P Zn 4EG and P Zn 5EG display dramatic color changes and spectral shifts upon the addition of Li + and K + , respectively. Because of the dramatic color changes that occurred upon binding, the determination of alkali metal ions would be possible.