Dodecanuclear Mn ^II –Gd ^III metallomacrocycles: magnetic and refrigerant responses

Two dodecanuclear metallomacrocycles with a {MnII6GdIII6} skeleton are synthesized by employing the Schiff base derived from the condensation of carbohydrazide and <i>o</i>-vanillin. The paramagnetic centers show a weak AF interaction without an out-of-phase response. These half-filled shell cations provide the largest number of unpaired electrons for a 3d-4f combination of paramagnetic centres, and profiting from this feature, their magnetocaloric response is studied.