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The reaction of di-tert-butyl dicarbonate (Boc2O) in the presence of the acylation catalyst 4-dimethylaminopyridine (DMAP) was examined with N-Boc or N-acyl cyanoglycinate. The couple Boc2O/DMAP was found to act as an efficient agent for selective C-tert-butoxycarbonylation affording multifunctional carbon compounds. © 2010 Georg Thieme Verlag Stuttgart New York. Source

Roncali J.,CNRS Angers Institute of Molecular Science and Technology
Advanced Energy Materials

An overview of various approaches for the realization of single-material organic solar cells (SMOCs) is presented. Fullerene-conjugated systems dyads, di-block copolymers, and self-organized donor-acceptor molecules all represent different possible approaches towards SMOCs. Although each of them presents specific advantages and poses specific problems of design and synthesis, these different routes have witnessed significant progress in the past few years and SMOCs with efficiencies in the range of 1.50% have been realized. These performances are already higher than those of bi-component bulk heterojunction solar cells some ten years ago, demonstrating that SMOCs can represent a credible approach towards efficient and simple organic solar cells. Possible directions for future research are discussed with the aim of stimulating further research on this exciting topic. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Biet T.,CNRS Angers Institute of Molecular Science and Technology | Avarvari N.,CNRS Angers Institute of Molecular Science and Technology

Electroactive ligands picoline-1,2,3-triazole-5-DM-TTF and lutidine-bis(1,2,3-triazole-5-DM-TTF) are synthesized by click chemistry following the ruthenium catalyzed azide-alkyne cycloaddition strategy. In the solid state structure of the bis(triazole) derivative, a tweezer conformation is observed, with the two TTF units arranged in a parallel manner. Cyclic voltammetry measurements show a splitting of the first oxidation wave, demonstrating sequential oxidation of the TTF donors in the intramolecular in through space mixed valence radical cation and then dication, suggesting that the tweezer conformation is maintained also in solution. A cobalt(ii) complex based on the chelating picoline-triazole ligand is described. The lutidine-bis-triazole ligand shows no chelating behavior in the two structurally reported cadmium(ii) complexes. In one of the complexes, the Cd(ii) center is coordinated by four triazole rings from four different ligands, while the other four triazole units establish hydrogen bonds with one axially coordinated water molecule. The second complex is a one-dimensional coordination polymer, containing the CdCl2 fragment, in which the repeating motif is a pentanuclear "Cd5Cl10" unit decorated with two TTF ligands coordinated in a ditopical mode through the triazole units. The TTF donors establish intra- and intermolecular S⋯S contacts. This journal is © the Partner Organisations 2014. Source

Chrysos M.,CNRS Angers Institute of Molecular Science and Technology | Verzhbitskiy I.A.,CNRS Angers Institute of Molecular Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics

The particularly weak isotropic spectrum of the recently reported nearly depolarized collision-induced Raman scattering band SF6(ν1)+N2(ν1) at room temperature was obtained and is presented here. The spectrum was extracted from high-quality measurements of two independent incident-field polarization scattering components. Its zero-order moment was found to be about 200 times smaller than that of its anisotropic counterpart. Agreement, both in spectral shape and in intensity, was found with predictions based on the dipole-induced dipole polarization model once corrected for the very substantial back-induction, dispersion, and dipole-induced quadrupole-induced dipole interaction mechanisms, all of which were considered within the model framework of two point-polarizable molecules. Quantum-mechanical calculations revealed a large contribution from bound and predissociating dimers that amounts to more than one-third of the total isotropic scattering intensity. © 2010 The American Physical Society. Source

Toma O.,CNRS Angers Institute of Molecular Science and Technology | Mercier N.,CNRS Angers Institute of Molecular Science and Technology | Botta C.,CNR Institute for Macromolecular Studies
European Journal of Inorganic Chemistry

Three bismuth complexes based on N-methyl-4,4′-bipyridinium (hMV +), (hMV)[Bi(hMV)Cl5] (1), and N-methyl-N′-oxide-4, 4′-bipyridinium (MVO+), [Bi(MVO)X4(dmso)] ·dmso [X = Cl (2), Br (3)], are reported. All three compounds show luminescence in the solid state with maxima at 545 nm (yellow for 1) and 560 nm (orange for 2 and 3) with quantum yields up to 10 %. Upon UV irradiation, 1 undergoes a color change from white to blue accompanied by a reduction of the photoluminescence intensity. The analysis of the crystal structure of the three complexes points to a photoinduced charge-transfer (PICT) process at the origin of the photochromism in 1. Three bismuth complexes based on N-methyl-4,4′- bipyridinium (hMV+), (hMV)[Bi(hMV)Cl5] (1), and N-methyl-N′-oxide-4,4′-bipyridinium (MVO+), [Bi(MVO)X4(dmso)]·dmso [X = Cl (2), Br (3)], show strong photoluminescence in the solid state. Upon UV irradiation, 1 undergoes a photoinduced charge-transfer (PICT) process resulting in a color change from white to blue. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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