Three-dimensional networks based on trinuclear motifs with tricomponent azide-carboxylate-tetrazolate cobridges: synthesis, structure and magnetic properties

Two 3D coordination polymers of MnII with azide and bifunctional zwitterionic ligands bearing both carboxylate and tetrazolate groups, 1-(carboxylatomethyl)-3-(5-tetrazolato)pyridinium (L1) and 1-(carboxylatoethyl)-4-(5-tetrazolato)pyridinium (L2), were synthesized, and structurally and magnetically characterized. They are formulated as [Mn3(L1)2(N3)4(H2O)2]n·4nH2O (1) and [Mn3(L2)2(N3)4(H2O)3]n·3.5nH2O (2). In both compounds, octahedral MnII ions are linked by the mixed (μ2-EO-N3)(μ2-syn,syn-COO)(μ2-N2,N3-CN4) (CN4 = tetrazolate and EO = end-on) triple bridges to give anionic linear trinuclear motifs. The motifs are connected through EE-N3 (EE = end-to-end) bridges to give layers and chains in 1 and 2, respectively, and the cationic pyridinium spacers serve to interlink the layers or chains into three-dimensional frameworks with the α-Po and CdSO4-type topology, respectively. Magnetic studies demonstrated that the magnetic interactions within and between the trinuclear motifs, through the tricomponent and EE-N3 bridges, respectively, are both antiferromagnetic in both compounds.