Synthesis and Characterization of a Cerium(IV) Coordination Polymer Containing Isonicotinic Acid Zwitterions

The synthesis and characterization of a new Ce(IV) coordination polymer (CP) of composition [Ce 4 O 2 (OH) 2 (NO 3 ) 2 (C 6 H 5 NO 2 ) 8 ](NO 3 ) 8 (CeINA), employing isonicotinic acid (INA) as the ligand and ceric ammonium nitrate ((NH 4 ) 2 [Ce(NO 3 ) 6 ], CAN) as the metal source, is reported. In CeINA the zwitterionic ligand (INA*) with a carboxylate and a pyridinium group is present. The structure of CeINA was solved from powder X‐ray diffraction (PXRD) data and refined using the Rietveld method. The crystal structure of CeINA contains isolated chains of edge‐sharing CeO 8 polyhedra as the inorganic building unit (IBU), which are coordinated through the carboxylate groups of the zwitterionic INA* ligands to form a monoperiodic CP. Nitrate anions coordinate to the IBU as well, but are also located between the IBUs. The title compound was characterized by thermogravimetric and variable‐temperature PXRD measurements, as well as elemental analysis, infrared, and X‐ray absorption spectroscopy (XAS). Additionally, the formation of CeINA was studied in situ via PXRD and XAS. The initial oxidation state of +IV of Ce was maintained during the course of the reaction leading to CeINA.