Novel dense organic-lanthanide hybrid architectures: syntheses, structures and magnetic properties

Six novel three-dimensional (3D) dense organic-lanthanide(III) frameworks with formula {[Ln(HBPTCA)(H2O)]center dot 3H(2)O} n [Ln = La (1), Ce (2), Sm (3)] and [Ln(4)(BPTCA)(3)(H2O)(4)](n) [Ln = Tb (4), Dy (5), Ho (6)] were obtained by reactions of the corresponding lanthanide nitrate salt with 4,4'-bipyridine-2,2', 6,6'-tetracarboxylic acid (H(4)BPTCA) under different conditions. Complexes 1-3 have the same structure with (4, 6(2))(2)(4(2), 6(10), 8(3)) topology, which is rare binodal (3, 6)-connecting rutile structure, while the complexes 4-6 also with the same structure have different topology of (4(2), 6)(4)(6, 8(2))(4)(4(3), 6(3))(4)(4(2), 6(4))(6)(4(4), 6(5), 8(5), 10). The results indicate that the reaction conditions have great influence on the structure of the resulted complexes in this system. In addition, the H(4)BPTCA was found to be an effective bridging ligand for construction of novel lanthanide-based dense hybrids, and two new coordination modes of the BPTCA(4)-were found in the complexes. The photoluminescent property of 4 and magnetic properties of 2, 5 and 6 were also investigated.