New method of beta-NaYF4: Yb3+, Er3+ synthesis by using beta-cyclodextrin

Fedorova, Anna; Fedulin, Andrey I.; Morozov, Igor

doi:10.1016/j.jfluchem.2015.07.003

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…The clear lattice fringes indicate the formation of the single-crystalline structure with a good crystallinity and the measured lattice spacing of about 0.3 nm corresponds to the (002) plane determined from the hexagonal phase of β-NaYF 4 with a space group of P63/m. [33,34] The doped trivalent lanthanide ions Tm 3+ , Yb 3+ , Gd 3+ are dispersed as guest atoms in the β-NaYF 4 host matrices. SEM image of the edge-on rods is shown in Fig.…”

Section: Ucnr Characterizationmentioning

confidence: 99%

Liquid crystal self-assembly of upconversion nanorods enriched by depletion forces for mesostructured material preparation

et al. 2018

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Monodisperse rod-like colloidal particles are known for spontaneously forming both nematic and smectic liquid crystal phases, but their self-assembly was typically exploited from the fundamental soft condensed matter physics perspective. Here we demonstrate that depletion interactions, driven by non-adsorbing polymers like dextran and surfactants, can be used to enrich the self-organization of photon-upconversion nanorods into orientationally ordered nematic and smectic-like membrane colloidal superstructures. We study thermodynamic phase diagrams and demonstrate polarization-dependent photon upconversion exhibited by the ensuing composites, which arises from the superposition of unique properties of the solid nanostructures and the long-range ordering enabled by liquid crystalline self-organization. Finally, we discuss how our method of utilizing self-assembly due to the steric and electrostatic interactions, along with attractive depletion forces, can enable technological uses of lyotropic colloidal liquid crystals and mesostructured composite materials enabled by them, even when they are formed by anisotropic nanoparticles with relatively small aspect ratios.

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Section: Ucnr Characterizationmentioning

confidence: 99%

Liquid crystal self-assembly of upconversion nanorods enriched by depletion forces for mesostructured material preparation

et al. 2018

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“…Интерес к изучению трифторацетатных комплексов различных металлов связан, в первую очередь, с возможностью получения простых и сложных фторидов при их термическом разложении [3][4][5][6], в том числе в виде наночастиц, фторидных твердых растворов [7] и фторидных стекол различного состава [8][9][10].…”

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A novel сalcium trifluoroacetate structure

Vasilyeva

Glazunova

Терещенко

et al. 2021

Fine Chem. Technol.

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Objectives. The study was devoted to considering the features of the synthesis and crystal structure of calcium trifluoroacetate Ca2(CF3COO)4·8CF3COOH and investigating the products of its thermal behavior.Methods. The compositions of the proposed structural form were characterized by various physicochemical methods (X-ray diffraction, IR spectroscopy), and the products of thermal decomposition were determined under dynamic vacuum conditions.Results. The reaction between calcium carbonate and 99% trifluoroacetic acid yielded a new structural type of calcium trifluoroacetate Ca2(CF3COO)4·8CF3COOH (I) in the form of colorless prismatic crystals unstable air. X-ray diffraction results confirmed the composition I: space group P21, with unit cell parameters: a = 10.0193(5) Å, b = 15.2612(7) Å, c = 16.3342(8) Å, β = 106.106(2)°, V = 2399.6(2) Å3, Z = 2. The structure is molecular, constructed from Ca2(CF3COO)4·8CF3COOH dimers. The end molecules of the trifluoroacetic acid were involved in the formation of intramolecular hydrogen bonds with oxygen atoms of the bidentate bridging anions CF3COO−. There were strongly pronouncedsymmetric and asymmetric absorption bands of COO and CF3-groups in the IR spectrum of the resulting compound in the range of 1200–1800 cm−1. The definite peak of the oscillation of the OH-group at 3683 cm−1 corresponds to the trifluoroacetic acid molecules present in the structure. The broadpeak of the valence oscillations in the range of 3300–3500 cm−1 is caused by the presence of intramolecular hydrogen bonds. Decomposition began at 250°C and 10−2 mm Hg with calcium fluoride CaF2 as the final decomposition product.Conclusions. We obtained a previously undescribed calcium–trifluoroacetic acid complex whose composition can be represented by Ca2(CF3COO)4·8CF3COOH. The crystal island structure is a dimeric molecule where the calcium atoms are bound into dimers by four trifluoroacetate groups. The complex was deposited in the Cambridge Structural Data Bank with a deposit number CCDC 2081186. Although the compound has a molecular structure, thermal decomposition leads to the formation of calcium fluoride characterized by a small particle size, which may further determine its applications.

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