Four (5,5)-connected three-dimensional metal organic materials based on pentacarboxylate ligand: Synthesis, structures and characterization

A new pentacarboxylate ligand, 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino) diisophthalic acid (H5L), was designed and used for the assembly of metal organic materials using Mn2+, Co2+, Cd2+ and Cu2+ as nodes. Four compounds, (Me2NH2)[Mn2L(H2O)]center dot 3DMF center dot 3H(2)O (1), (Me2NH2)[Co2L(H2O)]center dot 3DMF center dot 3H(2)O (2), (Me2NH2)[Cd2L(H2O)]center dot 3DMF center dot 3H(2)O (3) and [Cu4L(mu(3)-OH)(2)(NO3)(mu(2)-NMP)]center dot 4.5NMP center dot 2H(2)O (4) (DMF = dimethylformamide, NMP = N-methyl-2-pyrrolidone) have been synthesized and structurally characterized. Single crystal X-ray diffraction analyses show that 1 and 3 are isostructural, both based on {M-2(CO2)(5)} molecular building blocks (MBBs) and L ligands. The topology of the 5-connected anionic framework may be described as (4(4))(6(6)) (Schlafli symbol). Preliminary structural analysis indicates 2 may have the same structure as that of 1 and 3. 4 features a 5-connected 3D neutral framework based on "butterfly" {Cu-4(mu(3)-OH)(2)(COO)(5)} MBBs and L ligands. The corresponding Schlafli symbol is (4(6))(6(4)). N-2 sorption isotherms of 2 shows typical type I behavior with BET surface area of 1251 m(2) g(-1) and a micropore volume of 0.491 cm(3) g(-1). Luminescent analysis indicates 3 exhibits linker-localized emission. Magnetic investigation of 4 reveals overall antiferromagnetic interactions. The compounds were further characterized by infrared (IR) and thermogravimetric analyses (TGA).