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Updated: Jun 13, 2026
Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
High-spin ground states via electron delocalization in mixed-valence imidazolate-bridged divanadium complexes
Bettina Bechlars1, Deanna M D'Alessandro, David M Jenkins
1Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA.
Abstract:
The field of molecular magnetism has grown tremendously since the discovery of single-molecule magnets, but it remains centred around the superexchange mechanism. The possibility of instead using a double-exchange mechanism (based on electron delocalization rather than Heisenberg exchange through a non-magnetic bridge) presents a tantalizing prospect for synthesizing molecules with high-spin ground states that are well isolated in energy. We now demonstrate that magnetic double exchange can be sustained by simple imidazolate bridging ligands, known to be well suited for the construction of coordination clusters and solids. A series of mixed-valence molecules of the type [(PY5Me(2))V(II)(micro-L(br)) V(III)(PY5Me(2))](4+) were synthesized and their electron delocalization probed through cyclic voltammetry and spectroelectrochemistry. Magnetic susceptibility data reveal a well-isolated S = 5/2 ground state arising from double exchange for [(PY5Me(2))(2)V(2)(micro-5,6-dimethylbenzimidazolate)](4+). Combined modelling of the magnetic data and spectral analysis leads to an estimate of the double-exchange parameter of B = 220 cm(-1) when vibronic coupling is taken into account.
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