A bismuth-organic compound containing 2,2':6'2"-terpyridine (terpy) and 2-thiophenecarboxylate (TC), of the general formula (terpy)Bi(κ -TC) ⋅0.47 H O (BiOM-1), has been synthesized under hydrothermal conditions. Addition of a lanthanide nitrate solution to the reaction mixture led to statistical replacement of the bismuth centers, and yielded isomorphous lanthanide containing compounds Bi Ln OM-1 (Ln=Nd, Sm, Eu, Tb, Dy, Er, and Yb) that showed bismuth and/or ligand sensitized lanthanide-centered emission, and the first example of NIR emission from a lanthanide doped BiOM. The structure was determined by single-crystal X-ray diffraction, and the level and uniformity of lanthanide ion incorporation into the bismuth host was determined by ICP-OES and electron microprobe analysis. For the visible emitters, lifetime data and quantum yields are presented. A high efficiency of sensitization was calculated for the europium analog (50.1 %), showing significant improvement over previously reported europium thiophenecarboxylates. These novel materials may provide strategies to address concerns over the long-term sustainability of the rare earth elements, especially relating to optical devices.
A lanthanide series incorporating 2-thiophenecarboxylate and terpyridine is presented. Four structure types are observed with differences in the coordination number and nuclearity of the complexes attributed to the effects of the lanthanide contraction.
Two thorium(IV) compounds, [Th(H2O)4Cl4]·2(HPy·Cl) (1) and (HPy)3[Th3(H2O)2Cl10(OH)5]·4(HPy·Cl) (2) (HPy = pyridinium), were isolated from acidic aqueous solution.
The compounds were synthesized at room temperature and subsequently
characterized using single crystal X-ray diffraction along with Raman
and IR spectroscopies. Whereas compound 1 is built from
discrete mononuclear Th(H2O)4Cl4 units,
compound 2 consists of a novel hydroxo-bridged trimeric
[Th3(OH)5]7+ core. Such species are
largely absent from discussions of Th solution and solid-state chemistry
and their isolation may be attributed to outer coordination sphere
interactions that help stabilize the structural units; extensive hydrogen
bonding and π–π stacking interactions are present
in 1 and 2. Density functional theory calculations
were performed to predict the respective vibrational frequencies of
the structural units, and their relative stability was predicted at
the correlated molecular theory level. Small-angle X-ray scattering
analysis of [Th3(OH)5]7+ in water
indicates that the trimeric structural unit remains intact and that
it is indeed an important species that necessitates consideration
in geochemical models and for design of Th materials from water.
A series of lanthanide organic hybrid materials was synthesized via hydrothermal methods and structurally characterized using single-crystal X-ray diffraction. Four phases were obtained from reactions of La, Eu, and Tb ions with 1,10-phenanthroline (phen) and 2-thiophenecarboxylate (TC):Although each of the structures consists of homometallic ligand bridged dimers, the four distinct phases arise from subtle differences in ligand binding modes and supramolecular interactions. Ln doping was explored and resulted in analogous heterometallic systems, [Eu 2−x La x (pheny La y -4; y = 0.42, 0.67). The photoluminescent properties of the solid-state materials were assessed using steady-state and time-dependent techniques to obtain excitation and emission profiles, transition energies, and lifetimes. The La phase exhibited ligand-based emission, whereas both Eu and Tb phases produced characteristic red and green metal-centered emission, respectively. By comparison, the heterometallic compounds exhibited both Ln-and ligand-based emission and photoluminescent color tuning of emission chromaticity. Further examination revealed that the color tuning was dependent on the relative La/Eu or La/Tb ratios as well as the excitation wavelength. These compounds are a rare example of single-phase Ln hybrid materials built from molecular units that exhibit excitation-dependent photoluminescent color tuning in the solid state.
Three bismuth(III)-organic compounds, [Bi4Cl8(PDC)2(phen)4]∙2MeCN (1), [BiCl3(phen)2] (2), and [Bi2Cl6(terpy)2] (3), were prepared from solvothermal reactions of bismuth chloride, 2,6-pyridinedicarboxylic acid (H2PDC), and 1,10-phenanthroline (phen) or 2,2';6',2"-terpyridine (terpy). The structures were...
The synthesis and photoluminescent properties of four bismuth-organic compounds, their lanthanide doped analogs, and an isostructural europium complex are reported.
Two new nanosized lanthanide-doped materials (Sm and Eu) obtained by high-energy milling provided a suitable platform with solid-state photoluminescence properties for sensing applications.
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