Dicarboxylate-dependent structural diversity in amino-functionalized complexes: From mononuclear to multinuclear coordination polymer

Three amino-functionalized coordination polymers with different flexible V-shaped dicarboxylate ligands have been synthesized based on Cd salt and a rigid linear ligand L (L = 3,6-di(3-imidazolyl)benzene-1,2-diamine, H2HIP = 5-hydroxyisophthalic acid, H(2)ABA = bis(4-carboxylphenyl)amine, H(2)IBG = isophthaloylbisglycine): {[Cd(L)(1.5)(HIP)] center dot (H2O)}(n) (1), {[Cd-2(L)(ABA)(2)(H2O)] center dot (H2O)(2)}(n) (2) and {[Cd(L)(0.5)(IBG)] center dot (H2O)(2)}(n) (3). Complex 1 crystallizes in a mononuclear structure with a 3D hxg-d net. Complex 2 crystallizes in a tetranuclear fashion with a layer structure. Complex 3 shows an infinite rod-shaped secondary building unit (SBU) structure. It implies that the structural diversity in assembly process is determined by the flexibility of dicarboxylate ligands. These complexes were characterized by single crystal X-ray diffraction, infrared spectra, thermogravimetric analysis, elemental analysis, and powder X-ray diffraction measurements. Additionally, luminescent properties of 1-3 have also been explored and all exhibit significant red-shifted emission in the solid state at room temperature compared with free L ligand. (C) 2016 Elsevier B.V. All rights reserved.