Syntheses and characterization of novel lanthanide adamantine–dicarboxylate coordination complexes

Hydrothermal reactions of 1,10-phenanthroline (phen), 1,3-adamantanedicarboxylic acid (H2L) and lanthanide chlorides yielded six compounds: [Ln(L)(HL)(phen)] (Ln=Pr, 1; Nd, 2), [Ln(L)(HL)(phen)(H2O)] (Sm, 3; Eu, 4), [Tb(L)(HL)(phen)(H2O)]2·2H2O (5), [Er3(L)4(OH)(phen)]2 (6). Compounds 1–4 are structurally featured by one-dimensional polymeric chains; 5 hold binuclear structure constructed from eight-coordinated lanthanide center LnN2O6 of distorted bicapped trigonal prism bridged by dicarboxylate ligands; 6 shows that erbium ions are in mono and bicapped trigonal prismatic geometries, respectively, which are further connected by μ3-OH to give rise to trinuclear structure. Thermogravimetric analyses of 1, 3 and 5 were performed. Fluorescent measurements of 4 and 5 were carried out, respectively.