High-Pressure Investigation of a Five-Coordinate Dy Single-Molecule Magnet

The temperature and pressure dependence of the high-performing single molecule magnet, [Dy­(Mes*O)2­(THF)2Br] (1) {Mes* = 2,4,6-tri-tert-butylphenyl}, have been investigated. A new polymorph of 1 appears upon the introduction of pressure in the range from 0.08 to 2.92 GPa, as well as by cooling to temperatures below 259 K. Regardless of these phase changes, the Dy-OMes* and Dy–Br distances as well as the ab initio calculated energies of the first Kramers doublets remain nearly unaffected by external pressure up to 1.91 GPa. The calculated energy barrier to magnetic reversal (U eff calc) varies in the range from 850 to 950 cm–1 as a function of increasing pressure without a clear trend.