Abstract
Four series of lanthanide-based coordination polymers (LnCPs), namely [L-n(Br(4)bdc)(1.5)(MeOH)(3)] (1(Ln); Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy), [Ln(2)(Br(4)bdc)(2)(NO3)(2)(MeOH)(4)] (2(Ln); Ln = Ce, Pr, Nd, Sm), (Ln(Br(4)bdc)(NO3) (MeOH)] (3(Ln); Ln = Gd, Tb, Dy), and [Ln(2)(Br(4)bdc)(3)(H2O)(2.3)(MeOH)(2.7)] (4(Ln); Ln = Gd, Tb, Dy) have been syn-thesized by reacting hydrated lanthanide(m) salts with tetrabromobenzene-1,4-dicarboxylic acid (H(2)Br(4)bdc) in different solvents under solvothermal conditions. The structural diversity found in the system mainly resulted from the effects of anions, solvents, and the variation in the ionic radii of the lanthanide(m) ions. Compounds in series 1(Ln) feature a two-dimensional (2D) layered structure with sql topology based on {(Ln(COO)(2))(2)(mu-COO)(2)) secondary building units (SBUs). Compounds in series 2(Ln) and 3(Ln) comprise, respectively, infinite uniform and alternate chains of {Ln(COO)(2)}(n) SBUs that are assembled into a similar network topology to 1(Ln). Meanwhile, compounds in series 4(Ln) feature 3D coordination net-works of a pcu alpha-Po topological net consisting of binuclear {Ln(2)(COO)(3)} SBUs. The formation of poly-meric networks in series 1(Ln)-4(Ln) is facilitated by the numerous coordination sites of the ligand Br(4)bdc(2-) and the fact that its bromine atoms can participate in the formation of various types of intermolecular interactions. The solid-state photoluminescence studies on Eu- (1(Eu)) and Tb- (1(Tb), 3(Tb), 4(Tb)) containing compounds indicate that the Br(4)bdc(2-) ligands can efficiently sensitize Eu3+ and Tb3+ emission. Notably, such compounds exhibit highly sensitive fluorescence sensing for acetone, water, and Fe3+ ions via the fluorescence quenching effect. As the representatives of the series, activated 1(Eu), 2(pr), 3(Tb), and 4(Tb), show the maximum CO2 uptake capacities of 170.4, 273.7, 255.3, and 303.5 cm(3) g(-1), respectively, at 50 bar and 298 K with good repeatability of the adsorption desorption properties. Magnetic studies indicate that the Gd- and Dy-based compounds 1(Gd), 1(Dy), 3(Gd), 3(Dy), and 4(Gd) show simple paramagnetic behaviours, whereas compound 4(Dy) exhibits weak ferromagnetic interactions.