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solid acid catalyst for organic synthesis in ..

Some of these cluster compounds, prepared by solid state chemistry at high temperature, were further dissolved in various solvents, then constituting efficient precursors for elaboration of hybrid organic/inorganic metal cluster compounds by ligand exchange or by metathesis in soft chemistry that allows handling some ligands instable in the high temperature conditions of the metal cluster synthesis. The grafting of functional ligands on the metal cluster gave access to hybrid cluster units that were further used in the elaboration of nanomaterials in which the specific properties of both the metal cluster units (luminescence, magnetism, redox properties) and the functional ligands can coexist giving materials potentially useful in optoelectronic or biotechnology. For instance, cluster-dendrimer assemblings, functionalized silicon surfaces giving new type of molecular junctions, silica nanoparticles with luminescent properties or bifunctional magnetic and luminescent silica nanoparticles were obtained with octahedral metal clusters.

Department of catalytic processes of fine organic and bioorganic synthesis ..

1998An orthogonal solid phase support for the synthesis of oligodeoxyribonucleotides containing 3′‐phosphates and its application in the preparation of photolabile hybridization probes.

MCM-41 (Mobil Composition of Matter No

The CAMET and CASET links for the synthesis of protected oligopeptides and oligodeoxynucleotides on solid and soluble supports.

Abstract:
Zeolitic imidazolate frameworks (ZIFs), a subclass of metal-organic frameworks (MOFs), havebeen recently employed in various fields such as gas separation, catalysis, water purification anddrug delivery.1 Their high importance is due to their chemical and thermal stability in addition tothe flexibility of their design. ZIFs have been synthesized solvothermally or at room temperatureusing organic solvents (e.g. methanol, DMF) or pure water.2 The control of size and morphologyof crystals has been achieved using reverse microemulsion methods, microwave, ultrasoundassistedsyntheses and coordination modulation methods.1-3 Herein, we investigate a newsynthesis method where ZIF crystals are produced using the reaction-diffusion framework (RDF)in a gel medium at room temperature. The method is based on the diffusion of an outer solutionof the organic linker or mixed linkers into an agar gel containing the inner metal ions Zn(II)and/or Co(II) where a precipitation reaction takes place leading to the formation of the ZIFcrystals. A propagating supersaturation wave, initiated at the interface between the outer solutionand the gel matrix leads to a precipitation front endowed with a gradient of crystal sizes rangingbetween 100 nm and 55 μm along the same reaction tube. While the precipitation fronts of ZIF-8 and ZIF-67 travel the same distance for the same initial conditions, ZIF-8 crystals therein areconsistently smaller than the ZIF-67 crystals due to the disparity of their rate of nucleation andgrowth. The effects of temperature, the concentration of the reagents, and the thickness of thegel matrix on the growth of the ZIF crystals are investigated. We also show that by using RDF,we can envisage the formation mechanism of the ZIF crystals, which consists of the aggregationof ZIF nanospheres to form the ZIF-8 dodecahedrons. Moreover, using RDF the formation of asolid-solution ZIF via the incorporation of Co(II) and Zn(II) cations within the same frameworkis achieved in a controlled manner. Finally, we demonstrate that doping ZIF-8 by Co(II)enhances the photodegradation of methylene blue dye under visible light irradiation in theabsence of hydrogen peroxide.

Abstract:
TiO2 nanofibers were synthesized using electrospinning [Jamil et al Ceramics International 38 (2012) 2437–2441]. The nanofibers were polycrystalline and porous in nature having average diameter and length of ~150 nm and 200 µm, respectively. Fig. 1 (a) and (b) shows scanning electron microscope (SEM) and transmission electron microscope (TEM) image of TiO2 nanofibers, respectively. The bandgap of the nanofibers lies in optical range ˃ 3.2eV. Which showed relatively low photocatalytic degradation of toxic textile dyes (Fig. 2). To improve it photocatalytic activity we embedded Mn0.5Co0.5Fe2O4 nanoparticles into TiO2 nanofibers. Which showed improved photocatalytic activity for the degradation of toxic organic compound (Fig. 2). We are now investigating the effect of photocatalytic water splitting for hydrogen evolution. It is expected that these heterostructure nanofibers will show improve photocatalytic activity for hydrogen evolution via water splitting.

Catalysts | An Open Access Catalysis Journal from MDPI

Abstract:
TiO2 nanofibers were synthesized using electrospinning [Jamil et al Ceramics International 38 (2012) 2437–2441]. The nanofibers were polycrystalline and porous in nature having average diameter and length of ~150 nm and 200 µm, respectively. Fig. 1 (a) and (b) shows scanning electron microscope (SEM) and transmission electron microscope (TEM) image of TiO2 nanofibers, respectively. The bandgap of the nanofibers lies in optical range ˃ 3.2eV. Which showed relatively low photocatalytic degradation of toxic textile dyes (Fig. 2). To improve it photocatalytic activity we embedded Mn0.5Co0.5Fe2O4 nanoparticles into TiO2 nanofibers. Which showed improved photocatalytic activity for the degradation of toxic organic compound (Fig. 2). We are now investigating the effect of photocatalytic water splitting for hydrogen evolution. It is expected that these heterostructure nanofibers will show improve photocatalytic activity for hydrogen evolution via water splitting.

Abstract:
The study of semiconductor nanocrystals (NCs) is a very active research field, due to the wide range of applications, related to light-emission and absorption, photodetection, solar cells, light emitting diode or tunable emitters for bio-labeling1. One area is the development of detection techniques with high spatial resolution enabled by the small size of nanomaterials. As a representative example, nanometer probes of temperature can be very useful to obtain an accurate local value of temperature, particularly in catalysis where the activity and selectivity are temperature dependent. The key is to obtain the value of the local temperature inside the solution or inside the solid at the surface of the reactants. Certain catalytic reactions require high temperatures to occur so another challenge is to build a high local temperature probe (> 373 K). In this context, semiconductor NCs are promising objects to provide this precision due to the temperature dependence of their optical properties. We present here the synthesis of different types of NCs (Cd3P22, InP@ZnS3 and CdSe@CdS4), their capacities as nanothermometers for high temperatures (>340 K) and the conditions which have to be fullfilled for accurate measurements. Different parameters such as the wavelength, the intensity, the area and the full width at half maximum of emission were studied as a function of temperature. The studied temperatures ranges from room temperature to 540 K and the comparison between the different NCs is discussed.

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Catalysts, an international, peer-reviewed Open Access journal.

Alan Herbert Cowley was born in Manchester, England. He was educated at the University of Manchester, England, where he received the following degrees: Bachelor of Science with Honors in Chemistry in 1955, Master of Science in 1956, and Doctor of Philosophy in 1958. He was a Postdoctoral Fellow, and later an Instructor at the University of Florida during the period 1958-1960. During the years 1960-1961 he was a Technical Officer with the Exploratory Group of Imperial Chemical Industries (Billingham Division), England. From 1962 to 1988 he was at The University of Texas at Austin, where he held the following positions: Assistant Professor of Chemistry, 1962-1967, Associate Professor of Chemistry, 1967-1970, Professor of Chemistry, 1970-1984, George W. Watt Centennial Professor of Chemistry, 1984-1988. From 1988-1989, he was the Sir Edward Frankland Professor of Inorganic Chemistry at Imperial College, London, U.K. He returned to the University of Texas at Austin in 1989 and currently holds the Robert A. Welch Chair in Chemistry.

He is the author of over 500 publications

Awards :

Royal Society of Chemistry Award for Main-Group Element Chemistry, 1980 ;Centenary Medal and Lectureship, Royal Society of Chemistry, 1986; American Chemical Society Southwest Regional Award, 1986; Stiefvater Memorial Award and Lectureship, University of Nebraska, 1987; Elected a Fellow of the Royal Society (Britain's National Academy), 1988; Chemical Pioneer Award of the American Institute of Chemists, 1994; von Humboldt Prize, 1996; Chevalier dans l'Ordre des Palmes Académiques. Decoration awarded by the French Government, 1997; Honorary Doctorate, University of Bordeaux I, 2003; Elected a Corresponding Member of the Mexican Academy of Sciences, 2004; The University Co-operative Society Career Research Excellence Award, 2006; C. N. R. Rao Award and Lecture, New Delhi, India, 2007; Elected a Corresponding Member of the Göttingen Academy of Sciences, 2007; Elected a Member of the European Academy of Sciences and Arts, 2007; 2009 American Chemical Society Award for Distinguished Service in the Advancement of Inorganic Chemistry.

Other Honors :

Dalton Chemical Scholar, University of Manchester, 1956-1958; Deutsche Akademische Austauschdienst Fellowship, 1973; Guggenheim Fellowship, 1976-1977; Jeremy I. Musher Memorial Lectureship. The Hebrew University, Jerusalem, Israel, 1979; Appointed to the Editorial Board of Inorganic Chemistry, 1979-1983; Appointed to the Editorial Board of Chemical Reviews, 1984-1988; Chairman, Gordon Research Conference on Inorganic Chemistry, 1983; Appointed to the Board of Inorganic Syntheses, 1983-. Editor-in-Chief of Volume 31; Elected to Council of Gordon Research Conferences, 1984-1987; College of Natural Sciences Award for Teaching Excellence, 1984; Appointed to the Editorial Board of Polyhedron, 1984-1998; Mobay Lecturer, University of New Hampshire, 1985; Karcher Lecturer, University of Oklahoma, 1985; Appointed to the Editorial Board of the Journal of the American Chemical Society, 1986-1991; Elected Councilor, American Chemical Society, Division of Inorganic Chemistry, 1986-1989; Appointed to the Editorial Board of the Journal of Organometallic Chemistry, 1987-; Appointed to the American Chemical Society Committee on Divisional Activities, 1987-1989; Reilly Lecturer, University of Notre Dame, 1987; Appointed to the Air Force Office of Scientific Research Chemical Sciences Review Panel, 1987-1990; Appointed to the Editorial Board of Organometallics, 1988-1991; Appointed to the Editorial Board of Progress in Inorganic Chemistry, 1988- ; Appointed to the Editorial Board of Heteroatom Chemistry, 1988-1996; Elected to the Board of Trustees of the Gordon Research Conferences, 1989-1998; Appointed to the Editorial Board of Advances in Inorganic Chemistry, 1989 - ; Irvine Lecturer, St. Andrews University, Scotland, 1989; Fischel Lecturer, Vanderbilt University, 1991; Frontiers of Science Lecturer, Wayne State University, 1991; Appointed by Governor Richards of Texas to the Executive Board of Texas Science and Mathematics Renaissance Centers, 1991-93; Baxter Lecturer, Northern Illinois University, 1992; Appointed to the Scientific Committee of the European Journal of Solid State and Inorganic Chemistry, 1992-8.; Co-Chairman, First Gordon Research Conference on Science Education, 1992; Frontiers in Materials Science Lecturer, University of Iowa, 1993; Elected Vice-Chair, Gordon Research Conferences Board of Trustees, 1993; Elected Chair, Gordon Research Conferences Board of Trustees, 1994-95; Inaugural Etter Memorial Lecturer, University of Minnesota, 1995; President, International Council on Main Group Chemistry, 1997-98; Appointed to the International Advisory Board of Dalton Transactions, 1997-2000; Appointed Institut Universitaire de France Professor, 1999; Appointed to the Science and Engineering Advisory Board of ORFID, Inc., 2004; Appointed to the International Advisory Board of the Jordanian Journal of Chemistry, 2004; Gauss Professorship, Göttingen Academy of Sciences, 2006; F. G. A. Stone Lectureship, University of Bristol, U.K., 2007.

Research Interests

(1)Main group chemistry; (2)Organometallic chemistry; (3)Catalysis; (4)Precursors to electronic materials; (5)Inorganic polymers; (6)Environmental chemistry.

Catalysis Science & Technology

The partial introduction of electron rich elements (especially rhenium) in place of molybdenum in Chevrel phases allowed to control the electronic density in these compounds and to reach the magic number of 24 electrons per cluster, with three consequences: the stabilization of the metastable Mo6S8, the experimental confirmation of the energy diagramme of these materials (illustrated by the changes in transport properties), and the possible existence of rhenium octahedral clusters, provided the ligands were well selected. Indeed, a number of new compounds were synthesized by high temperature solid state reaction and structurally characterized. They belong to the ternary Re-Y-X (Y = chalcogen, X = halogen) and the quaternary diagrammes M-Re-Y-X (M = countercation, in most cases alkaline). Selecting both the total number of ligands and the halogen/chalcogen ratio, a wide variety of stackings were controlled, including molecular or ionic 0-D, 1-D, 2-D and 3-D structures that involve different types of bridges. Some of these compounds are soluble in polar organic solvents, and even in water for restricted examples, giving access to new organic/inorganic hybrids and a nonmaterial approach. Examples are the substitution of counter cations by organic (alkylammonium or TTF derivatives), organometallic, complex, solvated or kryptate ones, the substitution of halogen apical ligands by cyano, azo or pyrazine ligands.

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