Monothia [22]pentaphyrin(2.0.1.1.0): a core-modified isomer of sapphyrin.

A novel 22π-aromatic sapphyrin isomer endowed with an acene moiety was designed and realised for the first time as a core-modified monothia analogue. This macrocycle exhibited absorption and emission in the near-infrared region. It was diprotonated under strongly acidic conditions and bound to anions like sapphyrin. It showed unusual coordination chemistry, acting as a neutral ligand and undergoing large out-of-plane deformation to bind Pd(II) ions.