Structural and Magnetic Properties of Three One-Dimensional Nitrato-, Azido- and Phenoxido-Bridged Copper(Ii) Coordination Polymers

Three coordination polymers, 1∞[Cu3L2(NO3)]NO3·2MeOH·2H2O (1), 1∞[Cu3L2(N3)]CH3COO (2) and 1∞[Cu3L2(H2O)](ClO4)2 (3), based on the Schiff base H2L (H2L = N,N’-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine) have been synthesized and characterized. X-ray single-crystal analysis shows that compounds 1 and 2 are isostructural and crystallize in a non-centrosymmetric space group, P212121, while complex 3 crystallizes in a monoclinic system, space group P21/c. Compounds 1–3 consist of trinuclear complex entities, {Cu3L2}2+, connected via different bridges, nitrato (1), azido (2) and phenoxido (3), depending on the nature of the counterion. The cryomagnetic measurements reveal weak ferromagnetic interactions between the copper(II) ions bridged by the nitrato ligands in 1 (J = +1.026 cm−1, H = -JS1S2) and a weak antiferromagnetic coupling between the copper(II) ions connected by azido groups in 2 (J = -0.295 cm−1). The exchange interaction between the copper(II) ions connected by two phenoxido groups is antiferromagnetic, J = −12.780 cm−1.