Synthesis, structure and luminescent properties of lanthanide–organic frameworks based on pyridine-2,6-dicarboxylic acid

Pyridine-2,6-dicarboxylic acid (H2PDA) reacted with Dy2O3 under hydrothermal conditions to form a novel lanthanide–organic framework [Dy2(PDA)3(H2O)4]n·6nH2O (1). Compounds 1 crystallizes in monoclinic system, space group P21/c. In 1, a square motif as a building block constructed by four Dy3+ ions was further assembled into a highly ordered 2D (4,4) grid. While the self-assembly of H2PDA and Sm2O3 under hydrothermal conditions produced [Sm2(PDA)3(H2O)6]n·2nH2O (2). Compound 2 crystallizes in triclinic system, space group P-1, and shows a 1D coordination polymeric chain built from dimeric units of Sm3+ ions. Furthermore, the luminescent properties of both 1 and 2 were studied.