Hydrothermal Preparation, Crystal Structures, and Properties of New Mn(II) Metal-organic Frameworks with 4-bromoisophthalic Acid and N-donor Ligands

Two new coordination polymers, [Mn(Bript)(2,2′-bipy)] (1) and [Mn(Bript)(phen)(H2O)](H2O) (2), were prepared through hydrothermal reactions of Mn(II) acetate with H2Bript (H2Bript = 4-bromoisophthalic acid), and the N-donor ligands 2,2′-bipy and phen (2,2′-bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline). Both complexes were structurally characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Their X-ray crystal structures show that the two complexes belong to triclinic and monoclinic systems, P-1 space group for 1 and a = 9.389 (3) Å, b = 11.170 (3) Å, c = 16.629 (5) Å, α = 90.759 (3)°, β = 95.061(3)°, γ = 93.214(3)°, P2(1)/c space group for 2 and a = 12.980(14) Å, b = 11.120 (12) Å, c = 13.079(14) Å, β = 92.868(10)°, respectively. Complex 1 exhibits a 1D ladderlike chain, and then the neighboring 1D chains are further linked by the π⋅⋅⋅π stacking interactions to form a 2D supramolecular network. While complex 2 possesses a 2D layer structure, there also exists extensive intra- and intermolecular hydrogen-bonding interactions. The thermal stabilities of the two corresponding complexes have been briefly investigated.