Five MOFs with different topologies based on anthracene functionalized tetracarboxylic acid: syntheses, structures, and properties

Abstract

Five coordination polymers based on 5,5′-(2,3,6,7-tetramethoxyanthracene-9,10-diyl)diisophthalic acid (H₄L^OMe): [Mn₄(L^OMe)(OAc)₂(μ₃-OH)₂(NMP)₄(H₂O)₂]·2H₂O (1), [Ni₂(L^OMe)_0.5(H₂L^OMe)_0.5(μ₃-OH)(H₂O)₃]·6H₂O (2), [Cd₂(L^OMe)(H₂O)₂(NMP)]·2DMF·NMP·H₂O (3), [Co₂(L^OMe)(H₂O)₂]·2NMP·DMA·2H₂O (4), [Zn₂(L^OMe)(H₂O)₂]·2NMP·2H₂O·DOE (5) (NMP = N-methylpyrrolidone, DMF = N,N′-dimethylformamide, DMA = N,N′-dimethylacetamide, DOE = 1,4-dioxane) were prepared by solvothermal methods and characterized by elemental analysis (EA), single-crystal X-ray crystallography, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), and thermogravimetric analyses (TGA). X-ray crystallography analysis shows that complex 1 bears a two-dimensional (2D) (4,4) network based on tetranuclear secondary building units, which are further assembled into a three-dimensional supramolecular structure via π⋯π stacking interaction; complex 2 displays a 3D framework with fsc topology based on 2D 4⁴-sql layers and tetranuclear SBUs; complex 3 reveals a 3D PtS network via the L^OMe bridging dimetal {Cd₂O₁₁} units; complexes 4 and 5 possess 3D open frameworks with a rarely reported 3-nodal (4,4,4)-connected nou network. Moreover, magnetic susceptibility measurement of complexes 1 and 2 confirm the presence of magnetic exchange coupling among the metal ions of tetranuclear clusters, and fluorescent spectra of complexes 1, 3 and 5 show emission signals in the blue region.