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

Two new coordination polymers [Zn2L(2,2'-hPY)]n center dot (H2O)(2n) (1) and [Zn2L(phen)]n center dot (H2O)(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 (20) plane via intermolecular pi-pi interactions. Compound 2 belongs to the space group P (1) over bar and features a 1D Delta- and Lambda-typed chiral chain configuration despite the racemic nature for the whole complex. The neighboring chains with the same chirality are further stacked into a 20 Delta Delta Delta- or Lambda Lambda Lambda-typed supramolecular structure via intermolecular pi-pi 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. (C) 2010 Elsevier Masson SAS. All rights reserved.