Carbaporphyrin Dimers That Bear a Rigid Naphthalene Motif as an Internal Strap

The first fully connected aromatic carbaporphyrin dimer (6) and its bis-Pd complex (6-Pd2) that bear a rigid naphthalene motif as an internal strap were synthesized. These dimers consisted of two aromatic carbaporphyrins that shared a naphthalene motif. The π-electron conjugation of the obtained macrocycles was proposed to have two separated local 22 π-electron pathways and a 34 π-electron pathway. Their weak aromaticity was fully supported by 1H NMR spectroscopy, NICS values, ACID calculations, and ICSS plots.