Synthesis, structure, and magnetic properties of heterometallic trinuclear complexes {MII—LnIII—MII} (MII = Ni, Cu; LnIII = La, Pr, Sm, Eu, Gd)

Trinuclear heterometallic complexes containing the {M2Ln(Piv)6(NO3)} (MII = Ni, Cu; LnIII = Nd, Pr, Sm, Eu, Gd; Piv− is the anion of pivalic acid) and {Cu2Ln(Piv)8)]− (LnIII = Eu, Gd) metal cores were synthesized, their structures and magnetic properties were studied. For the most compounds, it was shown that their magnetic properties can be interpreted taking no interaction of the 3d-metal ions and a lanthanide into account. Ferromagnetic exchange interactions were found to exist between the unpaired electrons of the paramagnetic centers in the exchange clusters of the gadolinium-containing heterometallic complexes {M-Gd-M} (M = Ni or Cu).