Four copper(II) coordination polymers with a tetrachlorinated benzenedicarboxylate ligand: Solvent effect on diversiform supramolecular arrays

To further investigate the solvent effect on the structures of coordination polymers, a series of polymeric CuII complexes have been synthesized and characterized by single-crystal diffraction through combining of 2,3,5,6-tetrachloro-1,4-benzenedicarboxylic acid (H2BDC-Cl4) with CuII perchlorate. The products including {[Cu(BDC-Cl4)(py)3] · H2O}n (py = pyridine) (1), {[Cu(BDC-Cl4)(dioxane)(H2O)2] · dioxane}n (2), and {[Cu2(BDC-Cl4)2(DMF)4] · 2G}n (G = MeOH in 3 and G = EtOH in 4) have been obtained in different mixed solvents systems. With the change of the solvent system from pyridine/H2O (1:1) into dioxane/H2O (1:1), the infinite 1-D CuII-BDC-Cl4 chain motif in 1 is tuned into the 2-D (4,4) layered structure in 2 with the coordination of dioxanes to copper atoms. When the solvent system is changed into DMF/MeOH (1:1), then into DMF/EtOH (1:1), similar 1-D CuII-BDC-Cl4 double chains are afforded in 3 and 4 with different solvents inclusion. Moreover, the judicious choice of binding-guests leads to numerous coordination geometries of CuII centers and final dissimilar supramolecular lattices of 1–4 from 1-D to 3-D via robust hydrogen-bonding interactions. The spectroscopic, thermal, and fluorescent properties of 1–4 have also been investigated.