Synthesis of triple stranded porphyrin nanobelts

Abstract

Molecular nanobelts are fascinating analogs of carbon nanotubes. their rigid geometries and strongly coupled π-electrons have the potential to generate a wave function resembling that of a quantum ring. Here, we report the synthesis of triple stranded nanobelts consisting of 8 to 12 edge-fused porphyrin units with diameters of 21 to 32 angstroms. We synthesized these nanobelts by nickel-mediated coupling of meso-bromoporphyrins to form singly linked nanorings, followed by oxidation with gold(III) chloride. experimental 1H nuclear magnetic resonance spectra, supported by computational simulations, revealed that belts containing odd numbers of porphyrins, with circuits of 90 or 110 π-electrons, display global aromatic ring currents, whereas even-numbered belts, with 80, 100, or 120 π-electrons, are globally antiaromatic.