Syntheses, Structures, and Photoluminescences of Four Cd(II) Coordination Architectures Based on 1-(4-Pyridylmethyl)-2-methylimidazole and Aromatic Carboxylates: From One-Dimensional Chain to Three-Dimensional Coordination Architecture

The use of 1-(4-pyridylmethyl)-2-methylimidazole (pmmid) combined with four kinds of benzenecarboxylic acid ligands has allowed the rational design of four novel Cd­(II) coordination polymers (CPs), {[Cd­(pmmid)­(pa)­(H₂O)]·H₂O}<i>_n</i> (<b>1</b>), [Cd₂(pmmid)₂(cba)₄] (<b>2</b>), [Cd_1.5(pmmid)­(tbba)₃]_<i>n</i> (<b>3</b>), and {[Cd­(pmmid)­(pma)_0.5(H₂O)]·5H₂O}<i>_n</i> (<b>4</b>), [H₂pa = phthalic acid, Hcba = 4-chlorobenzoic acid, Htbba = 4-<i>tert</i>-butylbenzoic acid, and H₄pma = pyromellitic acid], which were synthesized by reactions of Cd­(OAc)₂·2H₂O and pmmid with aromatic acid under the ammoniacal condition and characterized by elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Complex <b>1</b> possesses a one-dimensional (1D) chain architecture, complex <b>2</b> is an interesting 1D structure containing two kinds of 1D chains, complex <b>3</b> features a two-dimensional <b>6</b>³ topological network structure, and complex <b>4</b> is a novel three-dimensional coordination architecture framework containing a T4(2)­10(2) water tape. In these complexes, the pmmid ligand takes a bidentate μ₂-η¹:η¹ coordination mode, and the four benzenecarboxylate ligands are able to link Cd­(II) ions in various coordination modes, giving these Cd­(II) complexes with different structures. In addition, complexes <b>1</b>–<b>4</b> exhibit luminescence in the solid state at room temperature