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

Two 3D coordination polymers of Mn-II with azide and bifunctional zwitterionic ligands bearing both carboxylate and tetrazolate groups, 1-(carboxylatomethyl)-3-(5-tetrazolato) pyridinium (L-1) and 1-(carboxylatoethyl)-4-(5-tetrazolato) pyridinium (L-2), were synthesized, and structurally and magnetically characterized. They are formulated as [Mn-3(L-1)(2)(N-3)(4)(H2O)(2)](n)center dot 4nH(2)O (1) and [Mn-3(L-2)(2)(N-3)(4)(H2O)(3)](n)center dot 3.5nH(2)O (2). In both compounds, octahedral Mn-II ions are linked by the mixed (mu(2)-EO-N-3)(mu(2)-syn,syn-COO)(mu(2)-N-2,N-3-CN4) (CN4 = tetrazolate and EO = end-on) triple bridges to give anionic linear trinuclear motifs. The motifs are connected through EE-N-3 (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 alpha-Po and CdSO4-type topology, respectively. Magnetic studies demonstrated that the magnetic interactions within and between the trinuclear motifs, through the tricomponent and EE-N-3 bridges, respectively, are both antiferromagnetic in both compounds.