Pd^II complexes of [44]-and [46]decaphyrins: The largest hückel aromatic and antiaromatic, and Möbius aromatic macrocycles

Reductive metalation of [44]decaphyrin with [Pd₂-(dba)₃] provided a Hückel aromatic [46]decaphyrin Pd^II complex, which was readily oxidized upon treatment with DDQ to produce a Hückel antiaromatic [44]decaphyrin Pd^II complex. In CH₂Cl₂ solution the latter complex underwent slow tautomerization to a Möbius aromatic [44]decaphyrin Pd_II complex which exists as a mixture of conformers in dynamic equilibrium. To the best of our knowledge, these three Pd_II complexes represent the largest Hückel aromatic, Hückel antiaromatic, and Möbius aromatic complexes to date.