Syntheses, Structures, and Photoluminescence of Lanthanide Coordination Polymers Based on 4‐Oxo‐1,4‐dihydro‐2,6‐pyridinedicarboxylic acid

Abstract

Investigating the coordination chemistry of H2CDA (4‐oxo‐1,4‐dihydro‐2,6‐pyridinedicarboxylic acid) with rare earth salts Ln(NO3)3 under hydrothermal conditions, structure transformation phenomenon was observed. The ligand, H2CDA charged to its position isomer, enol type structure, H3CAM (4‐hydroxypyridine‐2,6‐dicarboxylic acid). Six new lanthanide(III) coordination polymers with the formulas [Ln(CAM)(H2O)3]n [Ln = La (1), Pr, (2)] and {[Ln(CAM)(H2O)3]·H2O}n [Ln = Nd, (3), Sm, (4), Eu, (5), Y, (6)] were synthesized and characterized. The X‐ray structure analyses show two kinds of coordination structures. The complexes 1 and 2 and 3–6 are isostructural. Complexes 1 and 2 crystallize in the monoclinic C2/c space group, whereas 3–6 crystallize in the monoclinic system with space group P21/n. In the two kinds of structures, H3CAM displays two different coordination modes. The SmIII and EuIII complexes exhibit the corresponding characteristic luminescence in the visible region at an excitation of 376 nm.

Effect of single variable factor of electron‐acceptor on the luminescence quantum yield of terbium complex

“…Then, a rapid weight loss of about 85 % was due to the decomposition of the complex into terbium oxide (Figure S4). [31] Tb-I shows a slow weight loss of up to 289°C; this is followed by a rapid weight loss (observed 78 %; calculated 81 %, Figure S5).…”