Single Isomer Heterometallic {CrIII6MII2} Rings Templated by Tetramethylammonium

Rajeh Alotaibi; Edmund Little; Jonathan M Fowler; Adam Brookfield; Ralph W Adams; Amritroop Achari; Grigore A Timco; George F S Whitehead; Nicholas F Chilton; Rahul R Nair; David Collison; Richard E P Winpenny

doi:10.1021/acs.inorgchem.1c02342

Single Isomer Heterometallic {Cr^III₆M^II₂} Rings Templated by Tetramethylammonium

Inorg Chem. 2021 Oct 18;60(20):15675-15685. doi: 10.1021/acs.inorgchem.1c02342. Epub 2021 Oct 6.

Affiliations

¹ Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
² Department of Physics and Astronomy and National Graphene Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.

PMID: 34613713
DOI: 10.1021/acs.inorgchem.1c02342

Abstract

A family of heterometallic rings [Me₄N]₂[Cr^III₆M^II₂F₈(O₂C^tBu)₁₆] is reported using tetramethylammonium hydroxide pentahydrate as the source of a template, where M = Zn, Mn, Ni, and Co. The metal cores are octagons with metal-metal edges bridged by one fluoride and two carboxylate ligands. The divalent metal ions are found ordered at positions 1 and 5 in the octagon. The tetramethylammonium cations are above and below the metal plane of the ring in the crystal structure. Magnetic studies show antiferromagnetic coupling between the paramagnetic metal ions present, leading to paramagnetic ground states in each case. ¹H NMR spectroscopy confirms that the structure of the {Cr^III₆Co^II₂} ring exists in solution, and electron paramagnetic resonance spectroscopy confirms the magnetic structure of the other three rings.