The Experts below are selected from a list of 9732 Experts worldwide ranked by ideXlab platform
Augusto Cesar Goncalves - One of the best experts on this subject based on the ideXlab platform.
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the interaction of hg2 and Trivalent Ions with two new fluorescein bio inspired dual colorimetric fluorimetric probes
Dalton Transactions, 2016Co-Authors: Augusto Cesar Goncalves, V Pilla, Esther Arruda C Oliveira, Sergio M Santos, Jose Luis Capelo, A Dos A Santos, Carlos LodeiroAbstract:Two new luminescent compounds containing fluorescein–amino acid units have been designed and synthesized via an ester linkage between a fluorescein ethyl ester and Boc-Ser(TBDMS)-OH or Boc-Cys(4-MeBzl)-OH, and their photophysical properties have been explored. The optical response of both compounds (2 and 3) towards the metal Ions Na+, K+, Hg+, Ag+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+, Al3+, Fe3+, Ga3+and Cr3+ was investigated in pure acetonitrile and in acetonitrile/water mixtures. A strong CHEF (Chelation-Enhanced Fluorescence) effect was observed with all the Trivalent metals and Hg2+ Ions in both solvents. UV-vis absorption, steady state and time resolved emission spectroscopy methods were employed. The results show the formation of mononuclear complexes with Al3+, Fe3+, Ga3+, Cr3+, and Hg2+. Theoretical calculation using Density Functional Theory was performed in order to obtain atomistic insights into the coordination geometry of Al3+ and Hg2+ to the fluorescein 3, which is in accordance with the experimental stoichiometry results obtained in the Job's plot method. Among the active catIons, the minimum detectable amount is under 1 μM for most of the cases in both absorption and fluorescence spectroscopy methods.
G Adachi - One of the best experts on this subject based on the ideXlab platform.
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Tetravalent Ti 4+ Ion Conducting Ti(Nb 1-x W x ) 5/(5+x) (PO 4 ) 3 Solids
2020Co-Authors: N Imanaka, G Adachi, T UedaAbstract:Until now, many investigatIons on the ion conduction in solids have been undertaken and a large number of solid electrolytes whose conducting ion species were mono-, di-, and Trivalent Ions have been reported. Since the ion mobility in solids strongly depends on its valence state, the tetravalent cation has been regarded as an extremely poor-conducting species in solids due to the strong electrostatic interaction between the tetravalent ion and the surrounding anion species. In order to realize the tetravalent cation conduction in solids, it is necessary to reduce the above strong interaction by introducing the higher valent catIons than the conducting tetravalent ion into the structure. From the view point described above, we have successfully developed the tetravalent Zr 4+ Ceram. Soc., 47, 122 (1964)
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Trivalent ion conducting solid electrolytes
Solid State Ionics, 2000Co-Authors: Nobuhito Imanaka, Y Kobayashi, Shinji Tamura, G AdachiAbstract:Abstract A Trivalent ion conduction in solids was realized with Sc 2 (WO 4 ) 3 -type structure by the consideration of the stability and size of mobile Trivalent Ions and a structure to reduce the electrostatic interaction between the framework and the mobile ionic species as much as possible. Among the tungstates and the molybdates with the Sc 2 (WO 4 ) 3 -type structure, Sc 2 (WO 4 ) 3 and Sc 2 (MoO 4 ) 3 were found to hold the most suitable lattice size for Trivalent ion migration in the individual series. By the dc electrolysis and EPMA measurements, the mobile species was clearly identified to be Trivalent Ions in the Sc 2 (WO 4 ) 3 -type structure.
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Trivalent rare earth ion conduction in the rare earth tungstates with the sc2 wo4 3 type structure
Chemistry of Materials, 1998Co-Authors: Nobuhito Imanaka, Y Okazaki, Yasuyuki Kobayashi, K Fujiwara, Tsutomu Asano, G AdachiAbstract:To realize a Trivalent ion conduction in solids, the Sc2(WO4)3-type structure was chosen on the basis of the mobile Trivalent Ions and the structure which reduces the electrostatic interaction between the framework and the mobile Trivalent ionic species as much as possible. The typical conductivity of the rare earth tungstates R2(WO4)3 (R = Sc, Y, and Er−Lu) with the Sc2(WO4)3-type structure was found to be on the order of 10-5 S cm-1 at 600 °C. Among the rare earth tungstates, Sc2(WO4)3 (σ600°C = 6.5 × 10-5 S cm-1, Ea = 44.1 kJ mol-1) was found to be the most suitable size for the ionic conduction with regard to the relation between the mobile ion radius and the lattice size. The rare earth ion conducting characteristics were investigated by means of the rare earth concentration cell measurements and dc electrolyses. The electromotive force measurements with the Sc−Y binary alloy and the yttrium tungsten bronze as the electrodes strongly suggest the possibility of the Trivalent ion conduction of rare ear...
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Trivalent al3 ion conduction in aluminum tungstate solid
Chemistry of Materials, 1997Co-Authors: Yasuyuki Kobayashi, Nobuhito Imanaka, Shinji Tamura, Takashi Egawa, G AdachiAbstract:Ionic conduction of Trivalent aluminum in solid aluminum tungstate, Al2(WO4)3, has been directly and quantitatively demonstrated. Trivalent Ions, especially for aluminum where the polarizability is considerably low, are strongly bonded in a crystal lattice and have been believed to be unlikely to exhibit migration in solids because of high electrostatic interaction with the surrounding skeleton structure. The material, Al2(WO4)3, which has the Sc2(WO4)3 structure, was selected in order to reduce the interaction between the framework and the mobile species, Al3+, as much as possible. The ionic conduction characteristics of Al2(WO4)3 were investigated by means of electrolysis and electromotive force measurement by constructing an aluminum concentration cell. The typical electrical conductivity of Al2(WO4)3 was, approximately 2 × 10-5 S cm-1 at 800 °C. The dc electrolysis data strongly support the conclusion that ionic Al3+ is the mobile species in Al2(WO4)3. By further electrochemical measurements, it was c...
Carlos Lodeiro - One of the best experts on this subject based on the ideXlab platform.
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the interaction of hg2 and Trivalent Ions with two new fluorescein bio inspired dual colorimetric fluorimetric probes
Dalton Transactions, 2016Co-Authors: Augusto Cesar Goncalves, V Pilla, Esther Arruda C Oliveira, Sergio M Santos, Jose Luis Capelo, A Dos A Santos, Carlos LodeiroAbstract:Two new luminescent compounds containing fluorescein–amino acid units have been designed and synthesized via an ester linkage between a fluorescein ethyl ester and Boc-Ser(TBDMS)-OH or Boc-Cys(4-MeBzl)-OH, and their photophysical properties have been explored. The optical response of both compounds (2 and 3) towards the metal Ions Na+, K+, Hg+, Ag+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+, Al3+, Fe3+, Ga3+and Cr3+ was investigated in pure acetonitrile and in acetonitrile/water mixtures. A strong CHEF (Chelation-Enhanced Fluorescence) effect was observed with all the Trivalent metals and Hg2+ Ions in both solvents. UV-vis absorption, steady state and time resolved emission spectroscopy methods were employed. The results show the formation of mononuclear complexes with Al3+, Fe3+, Ga3+, Cr3+, and Hg2+. Theoretical calculation using Density Functional Theory was performed in order to obtain atomistic insights into the coordination geometry of Al3+ and Hg2+ to the fluorescein 3, which is in accordance with the experimental stoichiometry results obtained in the Job's plot method. Among the active catIons, the minimum detectable amount is under 1 μM for most of the cases in both absorption and fluorescence spectroscopy methods.
V Pilla - One of the best experts on this subject based on the ideXlab platform.
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the interaction of hg2 and Trivalent Ions with two new fluorescein bio inspired dual colorimetric fluorimetric probes
Dalton Transactions, 2016Co-Authors: Augusto Cesar Goncalves, V Pilla, Esther Arruda C Oliveira, Sergio M Santos, Jose Luis Capelo, A Dos A Santos, Carlos LodeiroAbstract:Two new luminescent compounds containing fluorescein–amino acid units have been designed and synthesized via an ester linkage between a fluorescein ethyl ester and Boc-Ser(TBDMS)-OH or Boc-Cys(4-MeBzl)-OH, and their photophysical properties have been explored. The optical response of both compounds (2 and 3) towards the metal Ions Na+, K+, Hg+, Ag+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+, Al3+, Fe3+, Ga3+and Cr3+ was investigated in pure acetonitrile and in acetonitrile/water mixtures. A strong CHEF (Chelation-Enhanced Fluorescence) effect was observed with all the Trivalent metals and Hg2+ Ions in both solvents. UV-vis absorption, steady state and time resolved emission spectroscopy methods were employed. The results show the formation of mononuclear complexes with Al3+, Fe3+, Ga3+, Cr3+, and Hg2+. Theoretical calculation using Density Functional Theory was performed in order to obtain atomistic insights into the coordination geometry of Al3+ and Hg2+ to the fluorescein 3, which is in accordance with the experimental stoichiometry results obtained in the Job's plot method. Among the active catIons, the minimum detectable amount is under 1 μM for most of the cases in both absorption and fluorescence spectroscopy methods.
D. Ehrt - One of the best experts on this subject based on the ideXlab platform.
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formation and uv absorption of cerium europium and terbium Ions in different valencies in glasses
Optical Materials, 2000Co-Authors: Heike Ebendorffheidepriem, D. EhrtAbstract:Abstract Cerium, europium and terbium Ions can exist in different valencies in glasses. The formation and ultraviolet (UV) absorption features of the Ions were studied in a fluoride phosphate (FP) and two phosphate glasses. Various melting conditIons and X-ray irradiation were applied to change the redox states of the Ions. Band separation of the UV absorption spectra was carried out to reveal the components and to determine their spectroscopic properties. The UV absorption spectra of the lower valent Eu2+, Tb3+ and Ce3+ Ions are due to 4f–5d transitIons, which are split in several bands by the local field around the rare-earth (RE) Ions. The crystal field splitting of the Trivalent Ions differs from the one of the divalent ion. The UV absorption spectra of the higher valent Eu3+, Tb4+ and Ce4+ Ions are caused by charge transfer (CT) transitIons from oxygen and fluorine to the RE Ions. The positIons and oscillator strengths of the 4f–5d and CT transitIons are studied in dependence on the RE and glass type. Furthermore, the ligand field strength of Eu2+ Ions is investigated. Redox tendency, site symmetry and charge of the RE Ions are important factors considering the influence of the RE type. Different polarizability and electron donor power of the ligands as well as different RE site symmetry in the glasses cause the compositional dependence of the transition properties.
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formation and uv absorption of cerium europium and terbium Ions in different valencies in glasses
Optical Materials, 2000Co-Authors: Heike Ebendorffheidepriem, D. EhrtAbstract:Cerium, europium and terbium Ions can exist in diAerent valencies in glasses. The formation and ultraviolet (UV) absorption features of the Ions were studied in a fluoride phosphate (FP) and two phosphate glasses. Various melting conditIons and X-ray irradiation were applied to change the redox states of the Ions. Band separation of the UV absorption spectra was carried out to reveal the components and to determine their spectroscopic properties. The UV absorption spectra of the lower valent Eu 2a ,T b 3a and Ce 3a Ions are due to 4f‐5d transitIons, which are split in several bands by the local field around the rare-earth (RE) Ions. The crystal field splitting of the Trivalent Ions diAers from the one of the divalent ion. The UV absorption spectra of the higher valent Eu 3a ,T b 4a and Ce 4a Ions are caused by charge transfer (CT) transitIons from oxygen and fluorine to the RE Ions. The positIons and oscillator strengths of the 4f‐5d and CT transitIons are studied in dependence on the RE and glass type. Furthermore, the ligand field strength of Eu 2a Ions is investigated. Redox tendency, site symmetry and charge of the RE Ions are important factors considering the influence of the RE type. DiAerent polarizability and electron donor power of the ligands as well as diAerent RE site symmetry in the glasses cause the compositional dependence of the transition properties. ” 2000 Elsevier Science B.V. All rights reserved.
