Novel Inorganic–Organic Hybrid Frameworks of Manganese(II): Syntheses, Crystal Structures, and Physical Properties

Three new inorganic–organic hybrid frameworks, [Mn2(BPTCA)(phen)2·H2O]n (1), [Mn4(BPTCA)2(H2O)10·2.5H2O]n (2), and [Mn2(BPTCA)(μ2-H2O)2]n (3) (BPTCA4− = 4,4′-bipyridine-2,2′,6,6′-tetracarboxylate; phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions. Complex 1 is a two-dimensional (2D) network constructed by infinite O−Mn−O−C−O−Mn- chains and BPTCA4− ligands, and an intriguing slide fastener-like three-dimensional (3D) framework structure is formed by the π···π interactions between the phen molecules. Complex 2 crystallized in a chiral space group P21 has a 2D network structure formed by Mn4 cluster units and BPTCA4− linkers, while complex 3 obtained at higher temperature than 2 is a 3D porous architecture. The result implies that the hydrothermal reaction temperature has a great influence on the structure of the complexes in this system. The magnetic behaviors of the complexes have been investigated and 2 showed modest powder second harmonic generation activity.