A Magnetocaloric Glass from an Ionic-Liquid Gadolinium Complex.

[Gd 5 (L) 16 (H 2 O) 8 ](Tf 2 N) 15 was obtained from reaction of Gd 2 O 3 with 1-carboxymethyl-3-ethylimidazolium chloride (LHCl). The material was found to be an ionic liquid that freezes to glassy state on cooling to -30 °C. Variable-temperature magnetic studies reveal the presence of weak magnetic intramolecular interactions in the glass. Isothermal variable-field magnetization demonstrates a magnetocaloric effect (MCE), which is the first finding of such an effect in a molecular glass. This MCE is explainable by an uncoupled representation, with a magnetic entropy change of -11.36 J K -1 kg -1 at 1.8 K for a 0-7 T magnetic field change, and with a refrigerant capacity of 125.9 J kg -1 , in the 1.8-50 K interval.