Heptanuclear Disk-Like M(3)(II)Ln(4)(III) (M = Ni, Co) Coordination Clusters: Synthesis, Structures and Magnetic Properties.

The synthesis, characterization, crystal structures and magnetic properties of isoskeletal heptanuclear disk-like M(3)(II)Ln(4)(III) coordination clusters with the general formula [Co(3)(II)Ln(4)(III)(mu(3)-OH)(6)L-6(CF3SO3)][(CF3SO3)(5)] where Ln = Gd (2), Y (3) and [Ni(3)(II)Ln(4)(III)(mu(3)-OH)(6)L-6(CF3SO3)][(CF3SO3)(5)] where Ln = Dy (4), Gd (5), Y (6) are presented. All the compounds are stable in solution as confirmed by ESI-MS. Magnetic studies were performed for compounds 2, 4, 5 and 6 and indicate ferromagnetic coupling while the magnetocaloric properties of 5 are characterized by Delta S-m = -15.4 J kg(-1) K-1 at T = 5.0 K and Delta T-ad = 5.9 K at T = 2.3 K, for mu(0)Delta H = 7 T.