A {Gd<sub>12</sub>Na<sub>6</sub>} Molecular Quadruple-Wheel with a Record Magnetocaloric Effect at Low Magnetic Fields and Temperatures
Thomais G. Tziotzi, David Gracia, Scott J. Dalgarno, Jürgen Schnack, Marco Evangelisti, Euan K. Brechin, Constantinos J. Milios
Abstract
High Resolution Image Download MS PowerPoint Slide Reaction of Gd(OAc) 3 ·4H 2 O, salicylaldehyde and CH 3 ONa in MeCN/MeOH affords [Gd 12 Na 6 (OAc) 25 (HCO 2 ) 5 (CO 3 ) 6 (H 2 O) 12 ]·9H 2 O.0.5MeCN ( 1 ·9H 2 O.0.5MeCN), whose structure describes a quadruple-wheel consisting of two {Na 3 } and two {Gd 6 } rings. The magnetic properties of 1 reveal very weak antiferromagnetic interactions between the Gd III ions, which give rise to a record magnetocaloric effect at low applied magnetic fields and low temperatures. The magnetic entropy change reaches −Δ S m = 29.3 J kg –1 K –1 for full demagnetization from B = 1 T at T = 0.5 K.