[30]Hexaphyrin(2.1.2.1.2.1) as Aromatic Planar Ligand and Its Trinuclear Rhodium(I) Complex.

Expanded porphyrins are attractive research targets because of their large and flexible structures, optical and electrochemical properties, and diverse coordination abilities. We are interested in the use of double bonds within expanded porphyrins because double bonds could conduct isomerization, expansion of π-conjugation, and giving different molecular geometry. We, thus, report [30]hexaphyrin(2.1.2.1.2.1) 3H-1, which was synthesized by a simple condensation reaction of 1,2-di(pyrrol-2-yl)ethene and pentafluorobenzaldehyde under an acidic condition. The compound 3H-1 exhibited 30π aromatic property with a highly planar structure, displaying intense Soret- and weak Q-like absorption bands. The compound 3H-1 has a sufficient space and dipyrrin-like coordination sites in its cavity. Trinuclear rhodium(I) complex 3Rh-1 was obtained with [Rh(CO)2Cl]2 and exhibited six redox potentials.