Publication Date

4-3-2024

Document Type

Article

Publication Title

Dalton Transactions

Volume

53

Issue

17

DOI

10.1039/d4dt00465e

First Page

7536

Last Page

7545

Abstract

Crystallization of the verdazyl-based valence tautomeric ion [Co(dipyvd)2]2+ (where dipyvd is the radical ligand 1-isopropyl-3,5-di(2′-pyridyl)-6-oxoverdazyl) with a variety of different counterions results in materials that show varying degrees of valence tautomeric (VT) transition in the solid state. The X-ray structure of the SbF6 salt at 150 K reveals a localized structure for the S = 1/2 tautomer, with a Co3+ cation and distinct anionic and radical ligands. Comparison with the structure of the same material at 300 K reveals large structural changes in the ligand as a result of the valence tautomeric equilibrium. Data for the S = 3/2 form is less conclusive; X-ray spectroscopy on the PF6 salt suggests a degree of low spin Co2+ character for the S = 3/2 tautomer at very low temperature though this is inconsistent with EPR data at similar temperatures and structural information at 150 K. Magnetic measurements on the [BArF4]− and triflate salts in organic solvents show that the VT equilibrium is dependent on solvent and ion pairing effects.

Funding Number

CHE-1900491

Funding Sponsor

U.S. Department of Energy

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

Department

Chemistry

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