The cerium(III) coordination polymer with mixed polycarboxylic acids. Preparation of the CeO2 nanoparticles by thermal decomposition of the polymer

A treatment of benzene-1,2,4,5-tetracarboxylic acid (H4btc) and pyridine-2,6-dicarboxylic acid (H2pydc) with Ce(NO3)3·6H2O (in the molar ratio 1:1:2) under hydrothermal conditions led to the formation of a new 1D cerium(III) coordination polymer {[(pydc)2Ce2(μ-H2btc)(H2O)6]·4H2O}n (1). Compound 1 was characterized by infrared spectroscopy, elemental analyses and by X-ray diffraction studies. The polymeric chain of 1 contains cerium(III) ions bridged by H2btc2− ligand. Each H2btc2− ion is connected to four cerium(III) ions via its two bidentate and bridging carboxylate groups. Cerium(III) ion is nine-coordinated by three oxygen atoms from two different H2btc2− ligands, two oxygen atoms and one nitrogen atom from the tridentate pydc2− ligand and three coordinated water molecules, resulting with a distorted tricapped trigonal prismatic arrangement. Many hydrogen bonds of the O–H⋯O type are also present in the crystal structure of 1 and assemble the polymeric chains and the co-crystallized water molecules into a 3D architecture. The coordination polymer 1 was used for the preparation of the CeO2 nanoparticles. Synthesized CeO2 nanoparticles were characterized by infrared spectroscopy, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The face-centered cubic structure of CeO2 was determined by PXRD.