Di‐2,7‐pyrenidecaphyrin(1.1.0.0.0.1.1.0.0.0) and Its Bis‐Organopalladium Complexes: Synthesis and Chiroptical Properties

Abstract

A non-aromatic expanded carbaporphyrinoid, incorporating two built-in 2,7-pyrenylene moieties was synthesized. The intrinsically labile structure was demonstrated by proton-triggered conformational changes between the figure-of-eight and quasi-Möbius conformers. Upon treatment with Pd(OAc) 2 , the reaction produces two bis-Pd II complexes with distinct coordination modes. Metal coordination serves to fix the macrocyclic frameworks with the net result that both bis-Pd II complexes could be resolved by high performance liquid chromatography (HPLC) on a chiral stationary phase. The isolated enantiomers showed persistent chiroptical properties as evidenced by the intense response in the circular dichroism (CD) spectra and the record high absorption dissymmetry factors (g abs of up to 0.038) seen in the near-infrared spectral region. Moreover, the mutual interconversion of these two Pd II complexes was found to be stereospecific and to favor the more stable isomers under weakly acidic conditions.

Nanographene-Fused Expanded Carbaporphyrin Tweezers

“…They have attracted interest for their π-conjugation pathways that differ from those of traditional tetrapyrrolic porphyrins as well as their own unique metal coordination chemistry. To date, polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, − anthracene, − phenanthrene, − triphenylene, and pyrene, − have been used to create carbaporphyrins. Recently, we reported that dibenzo­[ g , p ]­chrysene could serve as a building block to prepare a bis-dicarbacorrole, a highly twisted three-dimensional (3-D) cage structure, and a pyrene-containing belt-like system. − However, to the best of our knowledge, large π-extended PAHs, such as nanographenes, have yet to be introduced into carbaporphyrin frameworks.…”