The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Stéphane Cordier - One of the best experts on this subject based on the ideXlab platform.
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New ultra-violet and near-infrared blocking filters for energy saving applications: fabrication of tantalum Metal Atom cluster-based nanocomposite thin films by electrophoretic deposition
Journal of Materials Chemistry C, 2017Co-Authors: Thi Kim Ngan Nguyen, Stéphane Cordier, Benjamin Dierre, Adele Renaud, Maxence Wilmet, Noee Dumait, Serge Paofai, Wanghui Chen, Naoki Ohashi, Fabien GrassetAbstract:This study reports the first integration of inorganic tantalum octahedral Metal Atom clusters into multifunctional nanocomposite coating materials and devices for window technology and energy saving applications. [Ta6Br12i](n+) (n = 2, 3 or 4) cluster-based high visible transparency UV and NIR filters are realized. Green and brown colored films are fabricated by coating on an indium-doped tin oxide glass substrate by electrophoretic deposition, an industrialized solution process. The efficiency in energy saving of the new UV-NIR filters was estimated by the determination of different figure of merit (FOM) values, such as Tvis, Tsol and Tvis/Tsol (Tsol = solar transmittance and Tvis = visible transmittance), and the color coordinates (x, y, z and L*a*b). The Tvis/Tsol ratio is equal to 1.25 for the best films. Such values are evidence of a higher energy saving efficiency than most of the inorganic composites reported in the literature. These promising results pave the way for the use of transition Metal clusters as a new class of nanocoatings in energy saving window-based applications.
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Time-gated luminescence bioimaging with new luminescent nanocolloids based on [Mo6I8(C2F5COO)(6)](2-) Metal Atom clusters
Physical Chemistry Chemical Physics, 2016Co-Authors: Chrystelle Neaime, Maria Amela-cortes, Fabien Grasset, Yann Molard, Stéphane Cordier, Benjamin Dierre, Michel Mortier, Toshiaki Takei, Kohsei Takahashi, Hajime HanedaAbstract:Bioimaging and cell labeling using red or near infrared phosphors emitting in the ''therapeutic window'' of biological tissues have recently become some of the most active research fields in modern medical diagnostics. However, because organic and inorganic autofluorophores are omnipresent in nature, very often the background signal from fluorochromes other than targeted probes has to be eliminated. This discrimination could be available using a time-gated luminescence microscopy (TGLM) technique associated with long lifetime phosphorescent nanocomposites. Here, we report new SiO2 nanostructured particle (50 nm in diameter) embedded luminescent nanosized [Mo6I8(C2F5COO)(6)](2-) Metal Atom clusters (1 nm in diameter), successfully prepared by the microemulsion technique. This combination provides new physical insight and displays red emission in biological based solution under UV-Vis excitation with long lifetimes of around 17 and 84 mu s. Moreover, the nanoparticles can be internalized by cancer cells after surface functionalization by transferrin protein and clearly imaged by TGLM under excitation at 365 nm. The nanocomposites have been mainly characterized by scanning and transmission electron microscopies (SEM and HAADF-STEM), UV-Vis and photoluminescence (PL) spectroscopies.
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Advances in the Engineering of Near Infrared Emitting Liquid Crystals and Copolymers, Extended Porous Frameworks, Theranostic Tools and Molecular Junctions Using Tailored Re6 Cluster Building Blocks
Journal of Cluster Science, 2015Co-Authors: Stéphane Cordier, Fabien Grasset, Yann Molard, Konstantin A. Brylev, Yuri V. Mironov, Bruno Fabre, Nikolay G. NaumovAbstract:At the occasion of the fiftieth birthday of the introduction of the term 'Metal Atom cluster' by F. A. Cotton in inorganic chemistry, it is the good time to make a review on the advances in the engineering of molecular assemblies and nanomaterials based on octahedral Re6 Metal Atom clusters. The latter exhibit unique intrinsic structural and physicochemical properties (orthogonal disposition of Metallic sites that can be selectively functionalized, photoluminescence, redox, generation of singlet oxygen) that make them relevant building blocks for the structuration at the nanometric scale and functionalization of hybrid organic-inorganic materials and supramolecular frameworks. After synthesis by solid state chemistry techniques at high temperature, inorganic precursors built up on face-capped [(Re6Yi8)Ya6] cluster units (Y = chalcogen and/or halogen) can be functionalized via solution chemistry techniques or organic melts to form [(Re6Yi8)La6] (L = CN, OH, various organic ligands...). This work reports advances in the synthesis of [(Re6Yi8)Ya6] and [(Re6Yi8)La6] cluster units as well as on their use in the elaboration of supramolecular frameworks, nanoparticles, hybrid nanomaterials (co-polymers and liquid crystals) and active molecular junctions.
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Synthesis and characterization of A4[Re6Q8L6]@SiO2 red-emitting silica nanoparticles based on Re6 Metal Atom clusters (A = Cs or K, Q = S or Se, and L = OH or CN).
Langmuir, 2010Co-Authors: Tangi Aubert, Noriko Saito, Koji Kimoto, Fabien Grasset, Yann Molard, Hajime Haneda, Alexandra Y. Ledneva, Nikolay G. Naumov, Stéphane CordierAbstract:Metal Atom clusters constitute very promising candidates as luminophores for applications in biotechnology because they are nanosized entities offering robust luminescence in the near-infrared field (NIR). However, they cannot be used as prepared for biological applications because of potential toxic effects and quenching of the clusters' luminescence in aqueous media, and they therefore need to be dispersed in a biocompatible matrix. We describe herein the encapsulation of octahedral rhenium clusters, denoted as A(4)[Re(6)Q(8)L(6)] (A = Cs or K, Q = S or Se, and L = OH or CN), in silica nanoparticles by a water-in-oil microemulsion process, paying particular attention to the clusters' stability. The obtained A(4)[Re(6)Q(8)L(6)]@SiO(2) nanoparticles are 30 nm in size with good monodispersity and a perfectly spherical shape, as shown by scanning electron microscopy (SEM). The presence of cluster units inside the silica matrix was evidenced by scanning transmission electron microscopy in annular dark-field mode (ADF-STEM). From the point of view of their optical properties, the A(4)[Re(6)Q(8)L(6)]@SiO(2) nanoparticles show red and NIR emission under UV excitation, even when dispersed in water. The evolution of the structural and luminescence properties of clusters before and after encapsulation was followed by Raman and photoluminescence spectroscopy.
Fabien Grasset - One of the best experts on this subject based on the ideXlab platform.
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New ultra-violet and near-infrared blocking filters for energy saving applications: fabrication of tantalum Metal Atom cluster-based nanocomposite thin films by electrophoretic deposition
Journal of Materials Chemistry C, 2017Co-Authors: Thi Kim Ngan Nguyen, Stéphane Cordier, Benjamin Dierre, Adele Renaud, Maxence Wilmet, Noee Dumait, Serge Paofai, Wanghui Chen, Naoki Ohashi, Fabien GrassetAbstract:This study reports the first integration of inorganic tantalum octahedral Metal Atom clusters into multifunctional nanocomposite coating materials and devices for window technology and energy saving applications. [Ta6Br12i](n+) (n = 2, 3 or 4) cluster-based high visible transparency UV and NIR filters are realized. Green and brown colored films are fabricated by coating on an indium-doped tin oxide glass substrate by electrophoretic deposition, an industrialized solution process. The efficiency in energy saving of the new UV-NIR filters was estimated by the determination of different figure of merit (FOM) values, such as Tvis, Tsol and Tvis/Tsol (Tsol = solar transmittance and Tvis = visible transmittance), and the color coordinates (x, y, z and L*a*b). The Tvis/Tsol ratio is equal to 1.25 for the best films. Such values are evidence of a higher energy saving efficiency than most of the inorganic composites reported in the literature. These promising results pave the way for the use of transition Metal clusters as a new class of nanocoatings in energy saving window-based applications.
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Time-gated luminescence bioimaging with new luminescent nanocolloids based on [Mo6I8(C2F5COO)(6)](2-) Metal Atom clusters
Physical Chemistry Chemical Physics, 2016Co-Authors: Chrystelle Neaime, Maria Amela-cortes, Fabien Grasset, Yann Molard, Stéphane Cordier, Benjamin Dierre, Michel Mortier, Toshiaki Takei, Kohsei Takahashi, Hajime HanedaAbstract:Bioimaging and cell labeling using red or near infrared phosphors emitting in the ''therapeutic window'' of biological tissues have recently become some of the most active research fields in modern medical diagnostics. However, because organic and inorganic autofluorophores are omnipresent in nature, very often the background signal from fluorochromes other than targeted probes has to be eliminated. This discrimination could be available using a time-gated luminescence microscopy (TGLM) technique associated with long lifetime phosphorescent nanocomposites. Here, we report new SiO2 nanostructured particle (50 nm in diameter) embedded luminescent nanosized [Mo6I8(C2F5COO)(6)](2-) Metal Atom clusters (1 nm in diameter), successfully prepared by the microemulsion technique. This combination provides new physical insight and displays red emission in biological based solution under UV-Vis excitation with long lifetimes of around 17 and 84 mu s. Moreover, the nanoparticles can be internalized by cancer cells after surface functionalization by transferrin protein and clearly imaged by TGLM under excitation at 365 nm. The nanocomposites have been mainly characterized by scanning and transmission electron microscopies (SEM and HAADF-STEM), UV-Vis and photoluminescence (PL) spectroscopies.
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Advances in the Engineering of Near Infrared Emitting Liquid Crystals and Copolymers, Extended Porous Frameworks, Theranostic Tools and Molecular Junctions Using Tailored Re6 Cluster Building Blocks
Journal of Cluster Science, 2015Co-Authors: Stéphane Cordier, Fabien Grasset, Yann Molard, Konstantin A. Brylev, Yuri V. Mironov, Bruno Fabre, Nikolay G. NaumovAbstract:At the occasion of the fiftieth birthday of the introduction of the term 'Metal Atom cluster' by F. A. Cotton in inorganic chemistry, it is the good time to make a review on the advances in the engineering of molecular assemblies and nanomaterials based on octahedral Re6 Metal Atom clusters. The latter exhibit unique intrinsic structural and physicochemical properties (orthogonal disposition of Metallic sites that can be selectively functionalized, photoluminescence, redox, generation of singlet oxygen) that make them relevant building blocks for the structuration at the nanometric scale and functionalization of hybrid organic-inorganic materials and supramolecular frameworks. After synthesis by solid state chemistry techniques at high temperature, inorganic precursors built up on face-capped [(Re6Yi8)Ya6] cluster units (Y = chalcogen and/or halogen) can be functionalized via solution chemistry techniques or organic melts to form [(Re6Yi8)La6] (L = CN, OH, various organic ligands...). This work reports advances in the synthesis of [(Re6Yi8)Ya6] and [(Re6Yi8)La6] cluster units as well as on their use in the elaboration of supramolecular frameworks, nanoparticles, hybrid nanomaterials (co-polymers and liquid crystals) and active molecular junctions.
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Synthesis and characterization of A4[Re6Q8L6]@SiO2 red-emitting silica nanoparticles based on Re6 Metal Atom clusters (A = Cs or K, Q = S or Se, and L = OH or CN).
Langmuir, 2010Co-Authors: Tangi Aubert, Noriko Saito, Koji Kimoto, Fabien Grasset, Yann Molard, Hajime Haneda, Alexandra Y. Ledneva, Nikolay G. Naumov, Stéphane CordierAbstract:Metal Atom clusters constitute very promising candidates as luminophores for applications in biotechnology because they are nanosized entities offering robust luminescence in the near-infrared field (NIR). However, they cannot be used as prepared for biological applications because of potential toxic effects and quenching of the clusters' luminescence in aqueous media, and they therefore need to be dispersed in a biocompatible matrix. We describe herein the encapsulation of octahedral rhenium clusters, denoted as A(4)[Re(6)Q(8)L(6)] (A = Cs or K, Q = S or Se, and L = OH or CN), in silica nanoparticles by a water-in-oil microemulsion process, paying particular attention to the clusters' stability. The obtained A(4)[Re(6)Q(8)L(6)]@SiO(2) nanoparticles are 30 nm in size with good monodispersity and a perfectly spherical shape, as shown by scanning electron microscopy (SEM). The presence of cluster units inside the silica matrix was evidenced by scanning transmission electron microscopy in annular dark-field mode (ADF-STEM). From the point of view of their optical properties, the A(4)[Re(6)Q(8)L(6)]@SiO(2) nanoparticles show red and NIR emission under UV excitation, even when dispersed in water. The evolution of the structural and luminescence properties of clusters before and after encapsulation was followed by Raman and photoluminescence spectroscopy.
Kenneth J Klabunde - One of the best experts on this subject based on the ideXlab platform.
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gram scale synthesis of monodisperse gold colloids by the solvated Metal Atom dispersion method and digestive ripening and their organization into two and three dimensional structures
Journal of the American Chemical Society, 2002Co-Authors: Savka I Stoeva, Kenneth J Klabunde, C M Sorensen, I DragievaAbstract:We describe a synthetic procedure for preparation of large quantities of monodisperse thiol-stabilized gold colloids in toluene solution. The method is based on the solvated Metal Atom dispersion technique (SMAD), which is very suitable for preparation of large amounts of Metal colloidal solutions, as well as of Metal sulfide, Metal oxide, and other types of dispersed compounds in different solvents. A combination of two different solvents like acetone and toluene is used for the preparation of the gold colloids. The necessity of initially carrying out the SMAD reaction in acetone comes from its high degree of solvation of gold particles. Acetone acts as a preliminary stabilizing agent. After its removal from the system, the particles are stabilized by dodecanethiol molecules, which enable their very good dispersion in toluene solution. A digestive ripening procedure is carried out with the gold−toluene colloid, and for this purpose pure toluene as solvent is necessary. This has a dramatic effect on the n...
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xps studies of solvated Metal Atom dispersed smad catalysts evidence for layered cobalt manganese particles on alumina and silica
Journal of the American Chemical Society, 1991Co-Authors: Beng Jit Tan, Kenneth J Klabunde, Peter M A SherwoodAbstract:XPS studies of solvated Metal Atom dispersed (SMAD) catalysts coupled with detailed studies of reference compounds were carried out. It was shown that toluene-solvated cobalt Atoms nucleate at surface OH groups, and the resultant cobalt oxide surface species serve as sites for nucleation of more cobalt Atoms, leading to very small, reactive Metallic clusters. The surface of these clusters/particles are partially oxidized by adventitious oxygen or water, but when cobalt loadings of over 4% are used, a major portion of the catalytic particle remains Metallic. When solvated cobalt and manganese Atoms are mixed together, the manganese Atoms deposit first at surface OH sites, and manganese is highly dispersed in this way, but the majority ends up as surface MnO and Mn 2 O 3
Peter M A Sherwood - One of the best experts on this subject based on the ideXlab platform.
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xps studies of solvated Metal Atom dispersed smad catalysts evidence for layered cobalt manganese particles on alumina and silica
Journal of the American Chemical Society, 1991Co-Authors: Beng Jit Tan, Kenneth J Klabunde, Peter M A SherwoodAbstract:XPS studies of solvated Metal Atom dispersed (SMAD) catalysts coupled with detailed studies of reference compounds were carried out. It was shown that toluene-solvated cobalt Atoms nucleate at surface OH groups, and the resultant cobalt oxide surface species serve as sites for nucleation of more cobalt Atoms, leading to very small, reactive Metallic clusters. The surface of these clusters/particles are partially oxidized by adventitious oxygen or water, but when cobalt loadings of over 4% are used, a major portion of the catalytic particle remains Metallic. When solvated cobalt and manganese Atoms are mixed together, the manganese Atoms deposit first at surface OH sites, and manganese is highly dispersed in this way, but the majority ends up as surface MnO and Mn 2 O 3
I Dragieva - One of the best experts on this subject based on the ideXlab platform.
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gram scale synthesis of monodisperse gold colloids by the solvated Metal Atom dispersion method and digestive ripening and their organization into two and three dimensional structures
Journal of the American Chemical Society, 2002Co-Authors: Savka I Stoeva, Kenneth J Klabunde, C M Sorensen, I DragievaAbstract:We describe a synthetic procedure for preparation of large quantities of monodisperse thiol-stabilized gold colloids in toluene solution. The method is based on the solvated Metal Atom dispersion technique (SMAD), which is very suitable for preparation of large amounts of Metal colloidal solutions, as well as of Metal sulfide, Metal oxide, and other types of dispersed compounds in different solvents. A combination of two different solvents like acetone and toluene is used for the preparation of the gold colloids. The necessity of initially carrying out the SMAD reaction in acetone comes from its high degree of solvation of gold particles. Acetone acts as a preliminary stabilizing agent. After its removal from the system, the particles are stabilized by dodecanethiol molecules, which enable their very good dispersion in toluene solution. A digestive ripening procedure is carried out with the gold−toluene colloid, and for this purpose pure toluene as solvent is necessary. This has a dramatic effect on the n...