A new oxamato-bridged heterotrinuclear (NiCuNiII)-Cu-II-Ni-II complex with irregular spin state structure: Synthesis, spectroscopy, crystal structure and magnetism

A new oxamato-bridged (NiCuNiII)-Cu-II-Ni-II species, [Ni(tacn)(H2O)](2)[mu-Cu(pba)](ClO4)(2).6H(2)O 1, (tacn = 1,4,7-triazacyclononane; pba = 1,3-propylenebis(oxamato)) has been synthesized and structurally as well as magnetically characterized. Complex 1 has a discrete trinuclear (NiCuNiII)-Cu-II-Ni-II structure: Two nickel(II) ions are bridged by [Cu(pba)](2-) anion, macrocyclic ligand tacn works as terminal ligand of the nickel(II) center. The magnetic data of compound 1 was analyzed by means of (H) over cap = -J((S) over cap (Ni1) (.) (S) over cap (Cu) + (S) over cap (Ni2) (.) (S) over cap (Cu)) + D[(S) over cap (2)(z) - 1/3S(S + 1)] + beta[g(Ni)((S) over cap (Ni1) + (S) over cap (Ni2)) + g(Cu)(S) over cap (Cu)]H leading to g(Cu) = 2.19, g(Ni) = 2.18, J= -112.8 cm(-1), D = +/- 4.31 cm(-1). irregular spin state structure of complex 1 is also described here. (c) 2005 Elsevier B.V. All rights reserved.Chemistry, PhysicalSCI(E)EI0ARTICLE1-310-1575