CNRS The Institute of Chemistry and Processes for Energy, Environment and Health

Strasbourg, France

CNRS The Institute of Chemistry and Processes for Energy, Environment and Health

Strasbourg, France
SEARCH FILTERS
Time filter
Source Type

Imfeld G.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Vuilleumier S.,University of Strasbourg
European Journal of Soil Biology | Year: 2012

Extensive application of industrially-produced pesticides in agriculture has resulted in contamination of soil ecosystems. A variety of both cultivation-dependent and cultivation-independent methods can be applied to measure and interpret the effects of pesticide exposure. We review here the expanding panel of these methods in the specific context of responses of the soil bacterial microflora to pesticide exposure, and of ongoing advances in microbial molecular ecology, including metagenomics and new approaches for DNA sequencing. Several issues still need to be addressed in order to routinely evaluate the effect of pesticides on bacterial communities in soil in the future, and to make way for a widely accepted framework for risk assessment in agro-ecosystems that include bacterial indicators. © 2011 Elsevier Masson SAS.


Barbieri A.,CNR Institute for Organic Syntheses and Photoreactivity | Ventura B.,CNR Institute for Organic Syntheses and Photoreactivity | Ziessel R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Coordination Chemistry Reviews | Year: 2012

Transfer of excitation energy in natural systems is a fundamental process for light harvesting and propagation of information. The deep understanding of the energy transfer mechanisms and of the strategies for governing the directionality of the energy flow in artificial multichromophoric arrays is at the basis of their use in demanding fields such as solar energy conversion and optoelectronic applications. This review describes the recent activity of the authors in the synthesis and photophysical characterization of supramolecular arrays containing transition metal polypyridine complexes and organic units, with attention on the mechanisms and the pathways of the energy transfer processes that occur in the arrays. A topic of interest has been the exploitation of antenna effects as well as energy conduction in molecular wires. The design of the systems took into consideration several aspects that need to be balanced in the construction of efficient and useful arrays, in particular the spatial displacement of the units, their energy content distribution and the nature of the linkers that connect them. The latter point was of great relevance and the most recent studies afforded the preparation and the analysis of systems where the ligand is a large aromatic unit, that can both provide a structural role, a suitable electronic communication between the chromophores and an additional photoactive partnership. © 2012 Elsevier B.V.


Keller N.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Ducamp M.-N.,CIRAD - Agricultural Research for Development | Robert D.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Keller V.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Chemical Reviews | Year: 2013

Researchers suggest that photocatalytic oxidation has the potential approach to address he challenge of ethylene removal and fresh product storage. Photocatalysis is an emerging and promising technology whose development is driven by simultaneous efforts by research laboratories and industrials searching for innovative solutions to the environmental treatment of liquid and gaseous effluents and surfaces. This result from the advantages that photocatalysis can offer to the targeted application fields predicted by academic and industrial partners involved in the implementation of ecotechnologies or sustainable technologies. The wider industrial application of photocatalysis requires an important research effort at laboratory and industrial scales by demonstrating its performance under different storage and transport conditions.


Cretu O.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Botello-Mendez A.R.,Catholic University of Louvain | Janowska I.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Pham-Huu C.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | And 2 more authors.
Nano Letters | Year: 2013

The first electrical-transport measurements of monatomic carbon chains are reported in this study. The chains were obtained by unraveling carbon atoms from graphene ribbons while an electrical current flowed through the ribbon and, successively, through the chain. The formation of the chains was accompanied by a characteristic drop in the electrical conductivity. The conductivity of the chains was much lower than previously predicted for ideal chains. First-principles calculations using both density functional and many-body perturbation theory show that strain in the chains has an increasing effect on the conductivity as the length of the chains increases. Indeed, carbon chains are always under varying nonzero strain that transforms their atomic structure from the cumulene to the polyyne configuration, thus inducing a tunable band gap. The modified electronic structure and the characteristics of the contact to the graphitic periphery explain the low conductivity of the locally constrained carbon chain. © 2013 American Chemical Society.


Rodriguez-Manzo J.A.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Pham-Huu C.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Banhart F.,CNRS Institute of Genetics and of Molecular and Cellular Biology
ACS Nano | Year: 2011

Single and few-layer graphene is grown by a solid-state transformation of amorphous carbon on a catalytically active metal. The process is carried out and monitored in situ in an electron microscope. It is observed that an amorphous carbon film is taken up by Fe, Co, or Ni crystals at temperatures above 600 °C. The nucleation and growth of graphene layers on the metal surfaces happen after the amorphous carbon film has been dissolved. It is shown that the transformation of the energetically less favorable amorphous carbon to the more favorable phase of graphene occurs by diffusion of carbon atoms through the catalytically active metal. © 2011 American Chemical Society.


Iehl J.,CNRS Molecular Chemistry Laboratory | Nierengarten J.-F.,CNRS Molecular Chemistry Laboratory | Harriman A.,Northumbria University | Bura T.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Ziessel R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Journal of the American Chemical Society | Year: 2012

A sophisticated model of the natural light-harvesting antenna has been devised by decorating a C 60 hexa-adduct with ten yellow and two blue boron dipyrromethene (Bodipy) dyes in such a way that the dyes retain their individuality and assist solubility of the fullerene. Unusually, the fullerene core is a poor electron acceptor and does not enter into light-induced electron-transfer reactions with the appended dyes, but ineffective electronic energy transfer from the excited-state dye to the C 60 residue competes with fluorescence from the yellow dye. Intraparticle electronic energy transfer from yellow to blue dyes can be followed by steady-state and time-resolved fluorescence spectroscopy and by excitation spectra for isolated C 60 nanoparticles dissolved in dioxane at 293 K and at 77 K. The decorated particles can be loaded into polymer films by spin coating from solution. In the dried film, efficient energy transfer occurs such that photons absorbed by the yellow dye are emitted by the blue dye. Films can also be prepared to contain C 60 nanoparticles loaded with the yellow Bodipy dye but lacking the blue dye and, under these circumstances, electronic energy migration occurs between yellow dyes appended to the same nanoparticle and, at higher loading, to dye molecules on nearby particles. Doping these latter polymer films with the mixed-dye nanoparticle coalesces these multifarious processes in a single system. Thus, long-range energy migration occurs among yellow dyes attached to different particles before trapping at a blue dye. In this respect, the film resembles the natural photosynthetic light-harvesting complexes, albeit at much reduced efficacy. The decorated nanoparticles sensitize amorphous silicon photocells. © 2011 American Chemical Society.


Bura T.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Ziessel R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Organic Letters | Year: 2011

Water-soluble BODIPY dyes have been readily obtained by introduction of phosphonate fragments either on the boron for the green and yellow emitting dyes or on the side chain for the red emitting dyes. Hydrolysis of the phosphonate is realized at the end of the reaction sequence and allows isolation of the targets by precipitation. All these novel dyes are soluble and fluorescent in water with quantum yields in the 23-59% range and emission wavelength spanning from 667 to 509 nm. © 2011 American Chemical Society.


Laurichesse S.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Averous L.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Progress in Polymer Science | Year: 2014

Lignins are now considered as the main aromatic renewable resource they represent an excellent alternative feedstock for the elaboration of chemicals and polymers. Lignin is a highly abundant biopolymeric material that constitutes with cellulose one of the major components in structural cell walls of higher vascular plants. Large quantities of lignin are yearly available from numerous pulping processes such as paper and biorefinery industries. Lignin extraction from lignocellulosic biomass (wood, annual plant) represents the key point to its large use for industrial applications. One of the major problems still remains is its unclearly defined structure and its versatility according to the origin, separation and fragmentation processes, which mainly limits its utilization. While currently often used as a filler or additive, lignin is rarely exploited as a raw material for chemical production. However, it may be an excellent candidate for chemical modifications and reactions due to its highly functional character (i.e., rich in phenolic and aliphatic hydroxyl groups) for the development of new biobased materials. Chemical modification of lignin has driven numerous efforts and researches with significant studies during the last decades. After an overview with some generalities concerning the main extraction techniques along with the structure and the properties of lignins, this review describes in details the different chemical modifications of lignins they are classified into three groups: (1) lignin fragmentation into phenolic or other aromatic compounds for fine chemistry, (2) synthesis of new chemical active sites to impart new reactivity to lignin, and (3) functionalization of hydroxyl groups to enhance their reactivity. In that frame, the potential applications of lignin as precursor for the elaboration of original macromolecular architecture and the development of new building blocks are discussed. Finally, the major achievements and remaining challenges for lignin modifications and its uses as a macromer for polymer synthesis are also mentioned with emphasis on the most promising and relevant applications. © 2013 Elsevier Ltd.


Ziessel R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Ulrich G.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Haefele A.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Harriman A.,Northumbria University
Journal of the American Chemical Society | Year: 2013

An artificial light-harvesting array, comprising 21 discrete chromophores arranged in a rational manner, has been synthesized and characterized fully. The design strategy follows a convergent approach that leads to a molecular-scale funnel, having an effective chromophore concentration of 0.6 M condensed into ca. 55 nm3, able to direct the excitation energy to a focal point. A cascade of electronic energy-transfer steps occurs from the rim to the focal point, with the rate slowing down as the exciton moves toward its ultimate target. Situated midway along each branch of the V-shaped array, two chromophoric relays differ only slightly in terms of their excitation energies, and this situation facilitates reverse energy transfer. Thus, the excitation energy becomes spread around the array, a situation reminiscent of a giant holding pattern for the photon that can sample many different chromophores before being trapped by the terminal acceptor. At high photon flux under conditions of relatively slow off-load to a device, such as a solar cell, electronic energy transfer encounters one or more barriers that hinder forward progress of the exciton and thereby delays arrival of the second photon. Preliminary studies have addressed the ability of the array to function as a sensitizer for amorphous silicon solar cells. © 2013 American Chemical Society.


Poirel A.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | De Nicola A.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Ziessel R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health
Organic Letters | Year: 2012

The synthesis of unsymmetrical 3,5-dioligothienyl-BODIPY derivatives and their optical and redox properties are reported. The key step is the monobromination of the 2,6-dimethyl-3,5-dithienyl-BODIPY at the α position of the thiophene moiety. The additional thiophene modules are attached by palladium-catalyzed cross-coupling reactions. Increasing the number of modules on each side of the BODIPY core progressively shifts the absorption to 677 nm and the emission to 769 nm. © 2012 American Chemical Society.

Loading CNRS The Institute of Chemistry and Processes for Energy, Environment and Health collaborators
Loading CNRS The Institute of Chemistry and Processes for Energy, Environment and Health collaborators