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.

PdII insertion-triggered meso-carbon extrusion of N-fused pentaphyrin to form N-fused sapphyrin PdII complexes

meso-Carbon extrusion of N-fused [22]pentaphyrin(1.1.1.1.1) occurred upon its Pd^II complexation, giving N-fused [22]pentaphyrin (1.1.1.1.0) ([22]sapphyrin) Pd^II complexes 5 and 6 as 22π aromatic compounds. Oxidation of 5 with DDQ and Sc(OTf)₃ gave directly C-N linked dimer 7.

Palladium Complexes of Corroles and Sapphyrins

Palladium complexes of corrole and sapphyrin were prepared in high yield and fully characterized. The corrole provides a tetradentate/trianionic square planar coordination sphere for Pd^II , charge balanced by pyridinium. Both one and two Pd^II ions may be accommodated by the pentapyrrolic skeleton of the sapphyrin, and in each case the macrocycle acts as bidentate/monoanionic ligand and the inner-sphere square planar geometry is completed by allyl anions coordinated in an η³ fashion. NMR spectroscopy and X-ray crystallography data analyses uncovered the presence of interesting stereoisomers due to the flexibility of the ally ligands and also the pyrrole ring(s) that is/are not involved in metal binding.