Measurement of the Quantum Tunneling Gap in a Dysprosocenium Single-Molecule Magnet

William J A Blackmore; Andrea Mattioni; Sophie C Corner; Peter Evans; Gemma K Gransbury; David P Mills; Nicholas F Chilton

doi:10.1021/acs.jpclett.3c00034

Measurement of the Quantum Tunneling Gap in a Dysprosocenium Single-Molecule Magnet

J Phys Chem Lett. 2023 Mar 2;14(8):2193-2200. doi: 10.1021/acs.jpclett.3c00034. Epub 2023 Feb 22.

Authors

William J A Blackmore¹, Andrea Mattioni¹, Sophie C Corner¹, Peter Evans¹, Gemma K Gransbury¹, David P Mills¹, Nicholas F Chilton¹

Affiliation

¹ Department of Chemistry, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.

Abstract

We perform magnetization sweeps on the high-performing single-molecule magnet [Dy(Cp^ttt)₂][B(C₆F₅)₄] (Cp^ttt = C₅H₂^tBu₃-1,2,4; ^tBu = C(CH₃)₃) to determine the quantum tunneling gap of the ground-state avoided crossing at zero-field, finding a value on the order of 10^-7 cm^-1. In addition to the pure crystalline material, we also measure the tunnel splitting of [Dy(Cp^ttt)₂][B(C₆F₅)₄] dissolved in dichloromethane (DCM) and 1,2-difluorobenzene (DFB). We find that concentrations of 200 or 100 mM [Dy(Cp^ttt)₂][B(C₆F₅)₄] in these solvents increases the size of the tunneling gap compared to the pure sample, despite a similarity in the strength of the dipolar fields, indicating that either a structural or vibrational change due to the environment increases quantum tunneling rates.