Naphthylbipyrrole-Containing Amethyrin Analogue: A New Ligand for the Uranyl (UO 2 2+ ) Cation.

Using naphthobipyrrole as a functional building block, a new expanded porphyrin, naphthoisoamethyrin, was prepared in 85% yield under acid-catalyzed [4 + 2] MacDonald coupling conditions. Treatment of naphthoisoamethyrin with the nonaqueous uranyl silylamide salt [UO ₂ [N(SiMe ₃ ) ₂ ] ₂ ·2THF] yielded the corresponding uranyl complex. Upon metalation, naphthoisoamethyrin undergoes a two-electron oxidation to yield a formal 22 π-electron aromatic species, as inferred from ¹ H NMR and UV-vis spectroscopy, as well as cyclic voltammetry.