Synthesis and Guest Recognition Ability of 2,3-Dimethoxy-1 4-phenylene-Containing Porphyrinoids

The acid-catalyzed condensation of the bispyrrolylbenzene derivative and benzaldehyde yielded macrocycles 1 and 2 bearing three and four dipyrrin units which are connected by 2,3-dimethoxy-1,4-phenylene rings. The cationic guest recognition ability of 1 was investigated by UV-vis absorption, H-1 NMR spectroscopic techniques, and ab initio calculations (HF/3-21G(*)). The tris-dipyrrin macrocycle 1 was found to recognize alkali metals in the O-6 binding cavity.