Assembling ferromagnetically coupled (Cu, Gd) pairs: toward higher spin entities

Abstract

Abstract We have previously shown that in strictly dinuclear copper–gadolinium complexes, ferromagnetism is an intrinsic property of the Cu–Gd pair, yielding a S = 4 ground state. We want now to show that similar dinuclear complexes obtained with an original ligand having a supplementary oxygen donor atom are able to assemble in order to yield higher spin entities with a S = 8 ground state. These dimeric entities have four metallic centres, two Cu(II) and two Gd(III) ions, arranged at the vertices of a rectangle in such a way that two different ferromagnetic Cu-Gd interactions are operative. The stronger one (7 cm–1) is supported by a double phenolato bridge (CuO2Gd) and the weaker one (0.6 cm–1) by a single amido bridge (Cu–N–C–O–Gd).