Synthesis and structural characterization of two bis-imidazolium-linked cyclophanes: precursors toward ‘carbeneporphyrinoid’ ligands

The synthesis and spectroscopic characterization of the imidazolium-linked cyclophanes [1][PF6]2 and [2][PF6]2 are described. Cyclophane [1][PF6]2 contains two imidazolium rings bridged by a 2,6-bis(methyl)-pyridine unit and a 2,5-bis(methyl)-pyrrole unit. Cyclophane [2][PF6]2 contains two imidazolium rings bridged by two 2,5-bis(methyl)-pyrrole units. Cyclophanes [1][PF6]2 and [2][PF6]2 have been structurally characterized by X-ray crystallography.