Novel inorganic-organic hybrid frameworks of manganese(II): Syntheses, crystal structures, and physical properties

Three new inorganic-organic hybrid frameworks, [Mn-2(BPTCA)(phen)(2)center dot H2O]n (1), [Mn-4(BPTCA)(2)(H2O)(10)center dot 2.5H(2)O](n) (2), and [Mn-2(BPTCA)(mu(2)-H2O)(2)](n) (3) (BPTCA(4-) = 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-0-Mn- chains and BPTCA(4-) ligands, and an intriguing slide fastener-like three-dimensional (3D) framework structure is formed by the pi center dot center dot center dot pi interactions between the phen molecules. Complex 2 crystallized in a chiral space group P2(1) has a 2D network structure formed by Mn-4 cluster units and BPTCA(4-) 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.