Two birds with one stone: Self-assembly of metal–organic coordination complexes with discrete metallamacrocycle and 1D zigzag chain based on a flexible dicarboxylate ligand

To assemble metal–organic coordination complexes, a flexible dicarboxylate ligand, 2,2′-(4,6-dimethyl-5-nitro-1,3-phenylene)bis(methylene)-bis-(sulfanediyl)dibenzoic acid (H2L), has been designed and synthesized. Using the flexible ligand to assemble with copper ions, a mixture of two metal–organic complexes, Cu2(L)2(py)4·4dmso (1) and Cu2(L)2(py)6·3dmso·py (2), has been generated by solvothermal technology in one glass tube. Through increasing the mole fraction of pyridine, the pure phase of complex 2 was obtained. Both complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, and thermogravimetric analysis. Complex 1 is a discrete rectangular macrocycle. The guest solvents of dimethyl sulfoxide molecules were trapped in the cavity of rectangular metallmacrocycle, resulting in the formation of an infinite supramolecular metal–organic nanotube through van der Waals interactions between the guests and the host molecules. In complex 2, the flexible ligand adopts a syn conformation to assemble with copper ions to form an infinite one-dimensional zigzag chain.