Récepteurs oligopyridines-tétrathiafulvalène : synthèse et propriétés

Date du colloque : 06/2012</p

Tetrathiafulvalene-Polypyridyl Receptors for M2+ Recognition

Date du colloque : 06/2011</p

The parent tetrathiafulvalene-terpyridine dyad: synthesis and metal binding properties

The still unknown parent tetrathiafulvalene-terpyridine- ligand 5 (namely TTF-terpy), was synthesized through a straightforward strategy. The dyad exhibits an intramolecular charge transfer (ICT) which was evidenced by UV-vis electronic absorption. Complexation of various transition metal cations by this redox-active ligand was studied by UV-vis absorption spectroscopy as well as by cyclic voltammetry titration studies, supporting the dual functional character of this system. In addition, these results demonstrate that ligand 5 is a suitable building block for the preparation of electroactive neutral as well as charged metal complexes

Electroactive receptors incorporating Tetrathiafulvalene and polypyridyl units: synthesis and binding studies

Date du colloque : 07/2011</p

Nonlinear absorption reversing between an electroactive ligand and its metal complexes

We present the nonlinear absorption investigation of an electroactive ligand and two ruthenium and iron metal complexes under 532 nm, 30 ps laser excitation, by the open aperture Z-scan technique. Significant nonlinear optical parameters have in all cases been measured, while the nonlinear attribute has been found to change from saturable to reverse saturable absorption between the initial ligand and its complexes

Terpyridine-tetrathiafulvalene hybrid ligands and their electroactive metal complexes

The synthesis and full characterization (including X-ray structures) of two redox-active terpyridine-tetrathiafulvalene ligands namely (4-amido-2,2:6,2-terpyridyl)-6,7-ethylenedithiotetrathiafulvalene (1) and 2-(4-thioacetamide-2,2:6,2-terpyridyl)-3,6,7-tris(methylsulfanyl)-6, tetrathiafulvalene (2) are described. The binding properties of these multifunctional systems for various transition metal cations (Ni2+, Zn2+, Cd2+ and Fe2+) are analyzed in solution by cyclic voltammetry and UV-visible spectroscopy. In addition, a tetrahedral neutral zinc metal complex of ligand (2) formulated as (MeS)(3)-TTF-SCH2CONH-Tpy-ZnCl2 center dot MeOH [complex (3)] and an octahedral nickel complex formulated as [{(MeS)(3)-TTF-SCH2CONH-Tpy}(2)Ni]center dot(ClO4)(2)center dot 0.5(H2O) [complex (4)] are characterized in the solid state by X-ray diffraction

Opinion: Urban Resilience Efforts Must Consider Social And Political Forces

Environmental disasters, ranging from catastrophic floods to extreme temperatures, have caused more than 30,000 deaths per year and more than US$ 250–300 billion a year in economic losses, globally, between 1995 and 2015. Improved infrastructure and planning for extreme events is essential in urban areas, where an increasingly greater fraction of the world’s inhabitants reside. In response, international governmental and private initiatives have placed the goal of resilience at the center stage of urban planning. [For example, The 100 Resilient Cities Initiative (www.100resilientcities.org/); the Global Covenant of Mayors (https://www.compactofmayors.org/globalcovenantofmayors/); and the recent UN Habitat III (https://habitat3.org/the-new-urban-agenda)]. In addition, scientific and policy communities alike now recognize the need for “safe-to-fail” infrastructural design, and the potential role of green and blue infrastructure in mediating hydrological and climatic risks in cities

Systematic Study of Electron Localization in an Amorphous Semiconductor

We investigate the electronic structure of gap and band tail states in amorphous silicon. Starting with two 216-atom models of amorphous silicon with defect concentration close to the experiments, we systematically study the dependence of electron localization on basis set, density functional and spin polarization using the first principles density functional code Siesta. We briefly compare three different schemes for characterizing localization: information entropy, inverse participation ratio and spatial variance. Our results show that to accurately describe defect structures within self consistent density functional theory, a rich basis set is necessary. Our study revealed that the localization of the wave function associated with the defect states decreases with larger basis sets and there is some enhancement of localization from GGA relative to LDA. Spin localization results obtained via LSDA calculations, are in reasonable agreement with experiment and with previous LSDA calculations on a-Si:H models.Comment: 16 pages, 11 Postscript figures, To appear in Phys. Rev.

PLM adoption in SMEs context

The increasing market needs and technologies evolution, push companies to develop competitive advantages based on adequate and intensive use of information technology and communication (ICT). However, SMEs do not realize the importance of ICT adoption, which becomes vital for the development, and are not always well equipped to adopt and integrate them to their activities. The paper focused on issues regarding the ICT adoption, especially PLM solutions by SMEs. By analyzing the PLM definitions and works done, we explored indicators that impact positively or negatively ICT and PLM adoption. This paper proposes a model, currently theoretical, with empirical validation proposal through a survey