Polycrystalline samples of [Dy(Dtp) 2 ][Al{OC(CF 3 ) 3 } 4 ] were synthesised using the method described by Evans et al. 31.5 mg of sample was crushed with a mortar and pestle under an inert atmosphere, and then loaded into a borosilicate glass NMR tube along with 15.9 mg powdered eicosane, which was then evacuated and flame-sealed to a length of ca. 5 cm.