Synthesis and characterization of μ‐oxamido copper(II)‐iron(II) heterobinuclear complexes with an antiferromagnetic exchange interaction

Abstract

AbstractFour new μ‐oxamido heterobinuclear complexes have been synthesized and identified as [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N, N'‐bis(2‐aminopropyl)oxamido dianion and L represents diaminoethane (en); 1,3‐diaminopropane (pn); 1,2‐diaminopropane (ap) and 2,9‐dimethyl‐l,10‐phenanthroline (Me2‐phen). Based on the elemental analyses, spectroscopic studies, magnetic moments (at room temperature) and molar conductivity measurements, extended oxamido‐bridged structures consisting of a copper(II) and an iron(II) ions, which have a square planar environment and an octahedral environment, respectively, are proposed for these complexes. Complexes [Cu(oxap)Fe(en)2]SO4 (1) and [Cu(oxap)Fe(pn)2]SO4 (2) have been characterized by variable temperature magnetic susceptibility (4.2∼'300 K) and the observed data were least‐squares fitted to the susceptibility equation derived from the spin Hamiltonian including single‐ion aero‐field interaction for the iron(II) ion, H=−2JŜ1 ·;Ŝ2—DŜ2zl, giving the exchange integrals J=−21.9 cm−1 for 1 and J=−23.6 cm−1 for 2. These results are commensurate with antiferromagnetic interactions between adjacent metal ions within each molecule.