Ferromagnetic Spin-Coupling between Gadolinium(III) and Copper(II) Ions in Discrete Binuclear Gd(III)–Cu(II) Complexes

Abstract Three discrete binuclear gadolinium(III)–copper(II) complexes (CuGd(fsadien)NO3·5H2O (1), CuGd(hsapn)NO3·3H2O (2), and Gd(pvm)3Cu(A) (3)) have been synthesized; we use the notation H4fsadien=N,N′-bis(3-carboxysalicylidene)diethylenetriamine, H4hsapn=N,N′-bis(3-hydroxysalicylidene)-1,2-propanediamine, Hpvm=dipivaloylmethane (2,2,6,6-tetramethyl-3,5-heptanedione), and H2A=4-(6-methyl-8-oxo-2,5-diazanona-1,5,7-trienyl)imidazole. Magnetic susceptibility measurements (4.2–300 K) have revealed that the spin coupling between the Gd(III) and Cu(II) ions is ferromagnetic with coupling constants J=+2.3 cm−1 for (1), +5.7 cm−1 for (2), and +0.5cm −1 for (3), on the basis of the spin-Hamiltonian H=−2JSGd·SCu.