Synthesis and binding behavior of a Zn(II)-porphyrin having calix[5]arene cap

The synthesis and binding behavior of a Zn(II)–porphyrin having a calix[5]arene cap are presented. In order to synthesize such a bridged porphyrin, 5,15-bis(7-carboxy-1-naphthyl)-10,20-diphenylporphyrin having the syn arrangement of two naphthalene rings has been prepared. Amidation of the porphyrin and calix[5]arene having two amino functions and subsequent treatment of Zn(OAc)2 gave a calix[5]arene capped Zn–porphyrin. Calix[5]arene–Zn–porphyrin was found to bind 4-methylpyridine much stronger than TPP·Zn.