An Indium-Seamed Hexameric Metal-Organic Cage as an Example of a Hexameric Pyrogallol[4]arene Capsule Conjoined Exclusively by Trivalent Metal Ions

Durgesh V Wagle; Steven P Kelley; Gary A Baker; Kanishka Sikligar; Jerry L Atwood

doi:10.1002/anie.201914693

An Indium-Seamed Hexameric Metal-Organic Cage as an Example of a Hexameric Pyrogallol[4]arene Capsule Conjoined Exclusively by Trivalent Metal Ions

Angew Chem Int Ed Engl. 2020 May 18;59(21):8062-8065. doi: 10.1002/anie.201914693. Epub 2020 Feb 28.

Authors

Durgesh V Wagle¹, Steven P Kelley¹, Gary A Baker¹, Kanishka Sikligar¹, Jerry L Atwood¹

Affiliation

¹ Department of Chemistry, University of Missouri, 601 S. College Ave., Columbia, MO, 65211, USA.

PMID: 31849181
DOI: 10.1002/anie.201914693

Abstract

A hexameric metal-organic nanocapsule is assembled from pyrogallol[4]arene units, which are stitched together with indium ions. This indium-seamed capsule is the first instance of a M₂₄ L₆ type hexameric coordination cage held together exclusively by trivalent metal ions. Explicitly, unlike previously reported pyrogallol[4]arene-based metal-seamed capsules, the current In³⁺ seamed capsule is entirely supported by O→In coordinate bonds. This work demonstrates the important proof of concept of the ability of pyrogallol[4]arene to react with metals in higher oxidation states to assemble into atomically-precise hexameric coordination cages. As such, these results open up exciting avenues toward the assembly of previously unanticipated metal-organic capsules, for example offering inspiration for tackling metals exhibiting high valence states such as in the lanthanide and actinide series.

Keywords: coordination cages; indium; nanocapsules; pyrogallol[4]arene.