Synthesis, structure and magnetic properties of four unexpected di- and tetranuclear Robson-type macrocyclic complexes

Four symmetrical macrocyclic complexes, [Ni2L1(C6H4NO2)] (H2O)4 (1), [Cu4L1N3(ClO4)2(H2O)2]·[Cu2L1(ClO4)2(H2O)2 ]N3 (2), [Zn4L2 (H2O)2]·(ClO4)4 (3) and [Zn2L2(N3)2]CH3CN (4) (where H2L1 and H2L2 are the [2 + 2] condensation products of 2,6-diformyl-4-flurophenol with 1,3-diaminopropane and 1,4-diaminobutane, respectively), have been synthesized and characterized. The variable-temperature magnetisms of complexes 1 and 2 show that there are antiferromagnetic couplings between the two metal centers in both complexes, and the strongly electron-withdrawing fluorine groups in H2L weaken the antiferromagnetic exchange.