A Series of New Three-Dimensional d–f Heterometallic Coordination Polymers with Rare 10-Connected bct Net Topology Based on Planar Hexanuclear Heterometallic Second Building Units

A series of new three-dimensional (3D) d–f heterometallic coordination polymers, namely, [LnM­(μ5-PyIDC)­(μ2-INIC)­(μ3-INIC)]·xH2O [Ln = Sm, M = Co, x = 3 (1); Ln = Sm, M = Ni, x = 1 (2); Ln = Eu, M = Co, x = 3 (3); Ln = Eu, M = Cd, x = 3 (4); Ln = Eu, M = Zn, x = 3 (5); Ln = Gd, M = Co, x = 3 (6); Ln = Gd, M = Cd, x = 3 (7); Ln = Tb, M = Co, x = 3 (8); Ln = Tb, M = Cd, x = 2 (9); Ln = Tb, M = Zn, x = 3 (10); H3PyIDC = 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylic acid; HINIC = isonicotinic acid], have been successfully synthesized under hydrothermal conditions and structurally characterized. All the complexes are isostructural and exhibit novel 3D pillar-layered coordination frameworks constructed by the linkages of 2D heterometallic layers and INIC– pillars. Topological analysis indicates that those complexes possess a rare uninodal 10-connected bct topology based on planar hexanuclear heterometallic [Ln2M4(PyIDC)2] second building units. To the best of our knowledge, complexes 1–10 represent examples of 3D lanthanide–transition heterometal–organic coordination polymers with highly connected bct networks. Moreover, the luminescence properties of complexes 3–5 and 7–10 and the magnetic properties of 6–8 were also investigated.