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

[Image: see text] We perform magnetization sweeps on the high-performing single-molecule magnet [Dy(Cp(ttt))(2)][B(C(6)F(5))(4)] (Cp(ttt) = C(5)H(2)(t)Bu(3)-1,2,4; (t)Bu = C(CH(3))(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(C(6)F(5))(4)] dissolved in dichloromethane (DCM) and 1,2-difluorobenzene (DFB). We find that concentrations of 200 or 100 mM [Dy(Cp(ttt))(2)][B(C(6)F(5))(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.