ABSTRACT
Seven novel lanthanide coordination polymers, [Eu(STP)(glu)]n (1), [Ln4(STP)2(glu)5]n·4nH2O [Ln = Er (2), Yb (3)], [Ln(STP)(1,3-bdc)]n·0.5nH2O [Ln = Tb (4), Yb (5)], and [Ln(STP)(1,2-bdc)]n [Ln = Eu (6), Tb (7)] [NaSTP = sodium 2-(2,2':6',2â³-terpyridin-4'-yl)benzenesulfonate, H2glu = glutaric acid, H2(1,3-bdc) = benzene-1,3-dicarboxylic acid, H2(1,2-bdc) = benzene-1,2-dicarboxylic acid], have been prepared under hydrothermal conditions and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound (1) possesses a 2D layered structure based on 1D chains with STP- and glu2- anions acting as bridges. Compounds (2) and (3) are isomorphous and show a rare 3D tcj/hc net with a tetranuclear Ln3+ unit regarded as a seven-connected node and a glu2- anion serving as a three-connected node. Compounds (4) and (5) are isomorphous and exhibit six-connected pcu nets by denoting binuclear units to six-connected nodes. Compounds (6) and (7) display 3D 3,5T1 nets with (1,2-bdc)2- anions and dimetallic units serving as three- and five-connected nodes, respectively. The Eu compounds (1) and (6) demonstrate typically red emission, while the Tb compounds (4) and (7) exhibit characteristic green emission. The emission spectra of heteronuclear compounds [EuxTb1-x(STP)(1,2-bdc)]n (0 ≤ x ≤ 1) as efficient luminescent tags were investigated. The intermetallic energy transfer of Tb to Eu was also evaluated.
ABSTRACT
A new lanthanide-based framework, [Dy(STP)(1,2-bdc)]n (1), was constructed. It represents dysprosium(iii) 1D zigzag chains in a 3D framework and displays single-molecule magnet (SMM) behaviour with an energy barrier of 55.76 K under zero dc field.
ABSTRACT
Two series of lanthanide coordination polymers, [Ln(Hdpstc)(H2O)2]n·nH2O (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Yb (8)) and [Ln(Hdpstc)(phen)(H2O)]n·1.5nH2O (Ln = Pr (9), Nd (10), Eu (11), Tb (12)) (H4dpstc = 3,3',4,4'-diphenylsulfonetetracarboxylic acid and phen = 1,10-phenanthroline), have been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Isostructural compounds 1-8 and 9-12 exhibit (3,6)-connected 2D layered structures with Hdpstc3- anions as bridges. The Eu3+ and Tb3+ compounds exhibit bright red and green emissions with absolute quantum yields of 11.19% for 2-Eu, 26.05% for 4-Tb, 35.74% for 11-Eu, and 48.05% for 12-Tb. With a rational design strategy, we have constructed a series of Tb3+-doped Eu3+ materials emitting tunable three primary colors towards efficient white light emission with compounds 2-Eu and 4-Tb, and the absolute quantum yield of white light emission is 13.58%. Meanwhile, 4-Tb displays a highly sensitive response toward Fe3+ ions through significant fluorescence quenching of Tb3+.
