A new family of octanuclear Cu4Ln4 (Ln = Gd, Tb and Dy) spin clusters

The reaction of Cu(OAc)2 and Ln(OAc)3 (Ln = Gd, Tb and Dy) with 2-amino-2-methyl-1,3-propanediol (ampdH2) under solvothermal conditions has afforded a new family of isostructural octanuclear Cu4Ln4 complexes with the formula [Cu4Ln4(OAc)12(ampdH)8(OH2)2] (Ln = Gd (1), Tb (2) and Dy(3)) in good yield. Variable temperature magnetic susceptibility measurements reveal weak intramolecular exchange interactions for 1 and 2. Ferromagnetic coupling is observed for 1 and attributed to Cu...Gd interactions. In contrast, the magnetic susceptibility behaviour of 2 arises from a combination of intramolecular exchange interactions and the crystal field splitting of the (7)F6 ground state of the Tb(III) ions.