Incorporation of a tripodal ligand with a (N,O,O)-donor set into a new family of nickel and cobalt spin clusters

The reaction of Ni(OAc)2, NiX2 (X = Cl, Br) or CoCl2 with the proligand 2-amino-2-methyl-1,3-propanediol (ampdH2) affords a new family of tetranuclear complexes. The syntheses of [Ni4(OAc)4(ampdH)4] (1) and [M4X4(ampdH)4] (M = Ni, X = Cl, 2; M = Ni, X = Br, 3; M = Co, X = Cl, 4) are reported, together with the single crystal X-ray structures of 1, 2 and 4 and the magnetochemical characterization of 1, 3 and 4. Each member of this family of complexes displays a low symmetry structure that incorporates a {M4O4} core unit based on a distorted cubane. Magnetic measurements reveal ferromagnetic exchange interactions for 1, 3 and 4. These give rise to S = 4 ground state spins for the tetranuclear Ni complexes and an anisotropic effective S′ = 2 ground state for the Co complex.

Tetranuclear nickel(II) and cobalt(II) complexes of the monoanion of 2-amino-2-methyl-1,3-propanediol display related low symmetry structures based on distorted cubane units. Magnetic measurements reveal ferromagnetic exchange interactions for all complexes.Figure optionsDownload as PowerPoint slide