Synthesis, structures and magnetic properties of four new oxamidato-bridged heterobimetallic complexes

Four new heterobimetallic coordination polymers, namely, {[Cu(aeoe)M(H2O)3 · 2H2O]2}n (M = Mn(II) (1), Co(II) (2), Ni(II) (3)) and [Cu(aeoe)Ni(H2O)3]2 (4) (H4aeoe = N′-(2-aminoterephthalic acid)-N′′-(ethylenediamine)oxamidato) have been synthesized and characterized structurally. Complexes 1–3 are allomerism and feature 1-D ladder-like chain structure constructed from neutral tetranuclear complex units through the syn–anti carboxylate bridges, whereas complex 4 is a cyclic neutral tetranuclear complex unit. Their magnetic properties are also investigated based on their structures.