Three metal-organic frameworks prepared from mixed solvents of DMF and HAc

Three metal-organic framework compounds [HZn3(OH)(BTC)2(2H2O) (DMF)] · H2O (MOF-CJ3), [Co6(BTC)2(HCOO)6(DMF)6] (MOF-CJ4), and [Co18(HCOO)36] · 3H2O (MOF-CJ5) have been solvothermally synthesized in mixed solvents of DMF and HAc, respectively. These MOFs are characterized by single-crystal X-ray diffraction, X-ray powder diffraction, ICP, TG analyses, IR, and photoluminescence spectroscopy analyses. MOF-CJ3 crystallizes in tetragonal, space group I4cm (No. 108) with a = 20.588(3) Å, b = 20.588(3) Å, c = 17.832(4) Å. Its framework can be described as a 3D decorated (3, 6)-connected net based on the assembly of trigonal prismatic SBUs and triangular links. MOF-CJ4 crystallizes in hexagonal, space group P-3 (No. 147) with a = 13.975(2) Å, b = 13.975(2) Å, c = 8.1650(16) Å. The 2D network of MOF-CJ4 is constructed from [Co6(R(CO2)3)2(HCO2)6(DMF)6] (R = C9H3–) clusters and 1,3,5-benzene-tricarboxylates linkers. MOF-CJ5 crystallizes in triclinic, space group P1¯ (No. 2) with a = 15.205(3) Å, b = 18.005(4) Å, c = 21.500(4) Å, α = 71.21(3)°, β = 84.47(3)°, γ = 67.15(3)°. MOF-CJ5 has a diamond framework with Co-centered CoCo4 tetrahedra as nodes. It is noteworthy that the formic ligands in MOF-CJ4 and MOF-CJ5 are generated by the decomposition of DMF under acid conditions and incorporated into these two compounds.