No abstract

Hydrothermal reactions of lanthanide oxides with a rigid ligand (2,3-f)-pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid (H2PPDA) yielded 12 novel lanthanide coordination polymers with formulas [Ln(HPPDA)(PPDA)(H2O)2]·2H2O (Ln = Pr, 1·Pr; Nd, 2·Nd; Sm, 3·Sm; Eu, 4·Eu; Gd, 5·Gd; Tb, 6·Tb; and Dy, 7·Dy) and [Ln2 (PPDA)3 (H2O)4]·nH2O (Ln = Pr, n = 2, 8·Pr; Ln = Nd, n = 3, 9·Nd; Ln = Sm, n = 2,10·Sm; Ln = Eu, n = 1, 11·Eu; Ln = Gd, n = 1, 12·Gd). Single-crystal X-ray diffraction analysis reveals that they present two different structural types. Type I for 1·Pr−7·Dy possesses a two-dimensional 4·4 network, whereas type II for 8·Pr−12·Gd exhibits a two-dimensional framework with 3·6 topology. A rationalization for the synthetic pathways that lead to the formation of type I and type II is described. The synthetic reactions gave pure type I as the final product with the emergence of a small amount of type II as an intermediate within the reaction process. Photoluminescence, thermogravimetric, and magnetic analysis of type I were investigated.

= 2,6-bis[(3-methoxysalicylidene)hydrazinocarbonyl]pyridine, H 6 Bcshp = 2,6-bis[(3carboxylsalicylidene)hydrazinocarbonyl]pyridine), were synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction analysis. Due to the different anions, solvents and ligands used in the syntheses, complexes 1-4 exhibit diverse supramolecular structures constructed from the corresponding trinuclear copper units via H-bonds.