Zn(II) metal-organic frameworks (MOFs) assembled from semirigid multicarboxylate ligands: Synthesis, crystal structures, and luminescent properties

摘要

Two new coordination polymers [Zn2L(2,2′-bpy)]n·(H2O)2n (1) and [Zn_2L(phen)]n·(H_2O)_2n (2) have been assembled from a semirigid multicarboxylate ligand 3,3′-(1,3-phenylenebis(oxy))diphthalic acid (H4L) with the help of 2,2′-bipyridine (2,2′-bpy) or 1,10-phenanthroline (phen) as secondary ligand. Single crystal X-ray diffraction analysis reveals that complex 1 crystallizes in the space group C2/c and displays a one-dimensional (1D) chain structure constructed from 2,2′-bpy and L ligand, which further forms a two-dimensional (2D) plane via intermolecular π-π interactions. Compound 2 belongs to the space group P1 and features a 1D D- and L-typed chiral chain configuration despite the racemic nature for the whole complex. The neighboring chains with the same chirality are further stacked into a 2D △△△- or ЛЛЛ-typed supramolecular structure via intermolecular π-π interactions because of the chiral recognition mechanism. Photophysical properties over complexes 1 and 2 have been comparatively investigated, revealing the effect of secondary ligand on the luminescent properties of these two complexes.