Hydrothermal Synthesis and Characterization of Novel Lanthanide 2,2′‐Diphenyldicarboxylate Complexes

Lanthanide complexes with a one‐dimensional chain, [Ln 2 (dpdc) 3 (H 2 O) 2 ] n [Ln = La ( 1 ), Pr ( 2 ), Eu ( 3 ), Tb ( 4 ); dpdc = 2,2′‐diphenyldicarboxylate] were obtained by hydrothermal reaction of lanthanide( III ) chlorides and 2,2′‐diphenyldicarboxylic acid, and characterized by X‐ray diffraction. The crystal structure data reveal that they are isostructural. In the asymmetric unit, the two Ln 3+ ions are both eight‐coordinate but they have different coordination environments. Lanthanide ions arranged in a zigzag manner are bridged by the dpdc ligands into a 1‐D chain, while the structure appears like a pinwheel viewed along the c axis. In these complexes, 2,2′‐diphenyldicarboxylate anions exhibit tetradentate and pentadentate coordination modes. A laser‐induced highresolution spectrum (resolution: 0.2 cm −1 ) of 3 was obtained, which shows two Eu 3+ sites in 3 . This is in agreement with the results of single‐crystal X‐ray diffraction studies of 3 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)