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Abstract: The eight-coordinate (enH2)[YIII(pdta)(H2O)]2·10H2O (en=ethylenediamine and H4pdta=1,3-propylenediamine-N,N,N′,N′-tetraacetic acid) was synthesized, meanwhile its molecular and crystal structures were determined by single-crystal X-ray diffraction technology. The interaction between [YIII(pdta)(H2O)]2 2− and bovine serum albumin (BSA) was investigated by UV–vis and fluorescence spectra. The results indicate that [YIII(pdta)(H2O)]2 2− quenched effectively the intrinsic fluorescence of BSA via a static quenching process with the binding constant (K a) of the order of 104. Meanwhile, the binding and damaging sites to BSA molecules were also estimated by synchronous fluorescence. Results indicate that the hydrophobic environments around Trp and Tyr residues were all slightly changed. The thermodynamic parameters (ΔG =−25.20kJmol−1, ΔH= −26.57kJmol−1 and ΔS= −4.58Jmol−1 K−1) showed that the reaction was spontaneous and exothermic. What is more, both ΔH and ΔS were negative values indicated that hydrogen bond and Van der Waals forces were the predominant intermolecular forces between [YIII(pdta)(H2O)]2 2− and BSA. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis, characterization, and fluorescent spectra of rare-earth doped NaYF4 upconversion nanocrystals are introduced in this paper. The nanocrystals were synthesized in the water-ethanol-oleic acid system via a two-phase solvothermal approach, by using rare-earth stearate as the precursor. The as-prepared nanocrystals were of hexagonal phase, strong UC fluorescent intensity, with an average size of about 25 nm, which have been characterized by TEM, SAED, powder XRD, and luminescence spectroscopy. The possible mechanism of this synthesis that the nucleation and growth of nanocrystals occurred at the solid–liquid interface was also discussed. The nanocrystals are hydrophilic, and expected to fulfil the demand for biological applications via further modification. [Copyright &y& Elsevier]