Publications (12)72.08 Total impact
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Article: Self-assembly of charged Bodipy dyes to form Cassettes that display intracomplex electronic energy transfer and accrete into liquid crystals.
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ABSTRACT: Red- and blue-absorbing boron dipyrromethene dyes, bearing opposite electronic charges, associate in solution to form a 1:2 complex having a stability constant of ca. 10(17) M(-2). The complex can be dismantled by addition of a large excess of tetra-N-butylammonium cations. The same complex displays liquid crystalline properties on heating from rt to above 150 °C, as characterized by various experimental techniques. Highly efficient electronic energy transfer from the red to the blue dye occurs in both the initial complex and the subsequent mesomorphic state.Journal of the American Chemical Society 04/2012; 134(14):6100-3. · 9.91 Impact Factor -
Article: Near-infrared fluorescent nanoparticles formed by self-assembly of lipidic (Bodipy) dyes.
Chemistry 09/2011; 17(42):11709-14. · 5.93 Impact Factor -
Article: Excited-state properties of heteroleptic iridium(III) complexes bearing aromatic hydrocarbons with extended cores.
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ABSTRACT: The synthesis, complete structural characterization, electrochemistry, and excited-state dynamics of a series of four bis-heteroleptic iridium(III) charge-transfer complexes composed of a single acac-functionalized and two ortho-metalated 2-phenylpyridine ligands. The formed iodophenyl complex (2) was used as a metallosynthon to introduce extended-core ethynyltolyl (3), ethynylpyrene (4), and ethynylperylene (5) residues into these structures projecting from the acac ancillary ligand. Static and dynamic photoluminescence along with ultrafast and conventional transient absorption measurements in conjunction with cyclic voltammetry were employed to elucidate the nature of the intramolecular energy-transfer processes occurring in the excited states of polychromophores 4 and 5 and are directly compared with those of model complexes 2 and 3. Upon charge-transfer excitation of these molecules, the long-lived triplet-state metal-to-ligand charge-transfer ((3)MLCT)-based photoluminescence readily observed in 2 and 3 (τ = 1 μs) is nearly quantitatively quenched, resulting from production of the associated triplet intraligand ((3)IL) excited states in 4 and 5 through intramolecular triplet-triplet energy transfer. The respective formation of the extended-core (3)*pyrenyl and (3)*perylenyl-localized excited states in 4 and 5 is confirmed by their ultrafast excited-state evolution, which ultimately generates features associated with these (3)IL excited states and their greatly extended excited-state lifetimes with respect to the parent complexes 2 and 3.Inorganic Chemistry 09/2011; 50(21):10859-71. · 4.60 Impact Factor -
Article: Lanthanide ion extraction by trifluoromethyl-1,3-diketonate-functionalised ionic liquids adsorbed on silica.
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ABSTRACT: While acetylacetone (acacH) derivatives are, upon deprotonation, ubiquitous ligands in coordination chemistry, their potential to form stable ionic liquids has not been studied so far. Here we describe a straightforward synthesis of novel trifluoroacetylacetone-functionalised imidazolium salts. These salts are built from an imidazolium ring substituted on one side with a flexible chain of fixed length carrying a terminal acacH group and on the opposite side a paraffin chain of various lengths. By changing the length of these flexible chains (n=4, 8, 12) and the nature of the counter-anions (PF(6)(-), BF(4)(-), NTf(2)(-)), room-temperature ionic liquids were produced. Their application for the extraction of lanthanide salts (Eu, Tb) from dilute aqueous solution has been investigated. The presence of a strong UV absorber (imidazolium ring, λ(abs)=290 nm) allows photosensitisation of the Eu(III) and Tb(III) luminescence by efficient energy transfer, and thus extraction of these two lanthanides can be followed by fluorescence techniques. It appears that loading of the ionic liquids onto silica particles pre-treated with a dilute aqueous solution of NaOH is the most efficient way to obtain fast and almost quantitative (>99.9%) extraction of the metal ions as their diketonato complexes. The procedure is reproducible and the loaded SiO(2) particles can be simply treated with acid to strip the metal ions and regenerate the adsorbed (protonated) extractant.Chemistry 08/2011; 17(33):9113-22. · 5.93 Impact Factor -
Article: 3-Substituted-2,4-pentanedionates: ligands for photoactive supramolecular assemblies.
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ABSTRACT: Synthetic routes for the construction of 3-substituted 2,4-pentadionate ligands are broadly surveyed. They involve sequential alkylation and arylation by numerous methods, including those based on reactions of coordinated ligands, and can provide access to various rationally designed ligands. Applications of such ligands in the synthesis of multichromophoric complexes are illustrated in some detail. Incorporation of 3-substituted 2,4-pentanedione units into mesomorphic and macromolecular structures is considered in relation to structural control of energy and electron transfer processes in photoactive systems. Aspects of the general supramolecular chemistry of complexes of 3-substituted-2,4-pentadionate ligands are briefly discussed to illustrate the utility of such species within the full range of 1,3-dionate chemistry.Chemical Communications 07/2011; 47(40):11176-88. · 6.17 Impact Factor -
Article: Carborane-Bodipy scaffolds for through space energy transfer.
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ABSTRACT: Use of a closo-1,12-dicarbadecaborane backbone to link two different organic dyes separated by ca. 37 Å promotes exclusive through space electronic energy transfer with an efficiency of 81 to 87% with Stoke shifts between 4750 and 2800 cm(-1) depending on the pH.Chemical Communications 11/2010; 46(42):7978-80. · 6.17 Impact Factor -
Article: Hybrid complexes: Pt(II)-terpyridine linked to various acetylide-bodipy subunits.
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ABSTRACT: By tailoring the chemistry of the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (bodipy) core in order to change its spectroscopic properties, we linked some modified bodipy dyes to Pt(ii)-terpyridine centers thereby preparing three novel hybrid complexes. In one of such species, two pyrene subunits are also present. The absorption spectra and luminescence properties (both at room temperature in acetonitrile solution and at 77 K in butyronitrile rigid matrix) of the new hybrid complexes and of their bodipy parent species have been investigated, and compared with those of previously studied compounds. Absorption spectra showed that the different chromophoric subunits roughly keep their own features in the multicomponent systems, indicating the supramolecular nature of the compounds. Efficient photoinduced intercomponent energy transfer takes place in the various hybrid Pt(ii)-terpyridine-bodipy compounds, by taking advantage of different mechanisms: at room temperature in fluid solution very efficient energy transfer from the (3)MLCT state(s) of the Pt residue to the lowest-lying (3)bodipy is mediated by a charge transfer state via a two-step electron transfer process. Direct energy transfer from (3)MLCT state(s) to the (3)bodipy states takes place at 77 K, most likely via the Dexter mechanism. When two pyrene fragments are grafted to the boron, cascade energy transfer from the pyrene to the (1)bodipy also occurs by the Förster mechanism. For one of the new compounds, (3)bodipy emission with a maximum at 738 nm is also observed at cryogenic temperature.Physical Chemistry Chemical Physics 07/2010; 12(27):7392-402. · 3.57 Impact Factor -
Article: Luminescent ionic liquid crystals from self-assembled BODIPY disulfonate and imidazolium frameworks.
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ABSTRACT: A series of modular mesogenic salts based on the combination of anionic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (F-BODIPY) 2,6-disulfonate dyes and trialkoxybenzyl-functionalised imidazolium cations has been designed and synthesised. Each salt contains a rigid dianionic BODIPY core associated with two imidazolium cations functionalised by 1,2,3-trialkoxybenzyl (alkyl=n-C(8), n-C(12) or n-C(16)) units or, in one case, with imidazolium cations functionalised by a trialkylgallate (3,4,5-trialkoxybenzoate) unit in which the 3,5-dialkyl groups are terminated with a polymerisable acrylate entity. All these compounds were highly fluorescent in solution with quantum yields ranging from 54 to 62%. In the solid state, the width of the emission band observed at around 650 nm is a clear signature of aggregation. With the trialkoxybenzylimidazolium cations, polarised optical microscopy (POM) and X-ray scattering experiments showed that columnar mesophases were formed. Differential scanning calorimetry (DSC) studies confirmed the mesomorphic behaviour from room temperature to about 130 degrees C for salts with alkyl chains containing 8, 12 and 16 carbon atoms. The strong luminescence of the BODIPY unit was maintained in the mesophase and fluorescence measurements confirmed the presence of J aggregates in all cases. The salt containing the gallate-functionalised imidazolium cations showed no mesomorphism but the acrylate terminal units could be used to engender photoinitiated polymerisation thereby allowing the material to be immobilised on glass plates. The polymerisation process was followed by FTIR spectroscopy and the fixed and patterned films were highly fluorescent with a solid-state emission close to that of the complex in the solid state.Chemistry 06/2010; 16(24):7134-42. · 5.93 Impact Factor -
Article: Corrigendum: Luminescent Ionic Liquid Crystals from Self-Assembled BODIPY Disulfonate and Imidazolium Frameworks.
Chemistry 06/2010; 16(24):7057. · 5.93 Impact Factor -
Article: Borondipyrromethene dyes with pentane-2,4-dione anchors.
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ABSTRACT: New, acetylacetone-linked borondipyrromethene (BODIPY) dyes were readily obtained from BODIPY cores by various protocols involving direct grafting with acetylacetone or cross-coupling from a preorganized phenylacacH derivative bearing either an iodo or an ethynyl function. Facile anchoring on TiO(2) powder is obtained and scrutinized by FT-IR spectroscopy.Organic Letters 02/2010; 12(3):408-11. · 5.86 Impact Factor -
Article: Ionic liquid crystals formed by self-assembly around an anionic anthracene core.
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ABSTRACT: We have designed and synthesised a series of modular, mesogenic complexes based on anthracene-2,6-disulfonate and trialkoxybenzyl-functionalised imidazolium cations. Each complex contains a central, rigid, dianionic anthracene core and two flexible monocations bearing paraffin chains anchored on imidazolium rings. Anthracene-2,6-disulfonate can be crystallised with various simple alkylammonium ions and, in the case of +N(CH3)2(C16H33)2, a crystal structure determination has shown that the long paraffinic chains are intercalated between the anthracene moieties. The dianion forms columnar mesophases with trialkoxybenzylimidazolium cations, as identified by polarising optical microscopy and X-ray scattering measurements. Differential scanning calorimetry studies confirmed mesomorphic behaviour from room temperature to about 200 degrees C for alkyl chains containing 8, 12 and 16 carbon atoms. The strong luminescence of anthracene is maintained in the mesophase and fluorescence measurements confirmed the presence of J aggregates in all cases. The new functional materials described herein provide an easy access to stable and luminescent mesomorphic materials engineered by an ionic self-assembly process.Chemistry 08/2009; 15(33):8163-74. · 5.93 Impact Factor -
Article: Terpyridine-functionalized imidazolium ionic liquids.
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ABSTRACT: This paper reports the synthesis and the physical characterization of a new family of chelating ionic liquids carrying a terpyridine fragment suitable for metal extraction.Chemical Communications 04/2009; · 6.17 Impact Factor
Top co-authors
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Institutions
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2010–2011
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Université de Strasbourg
Strasbourg, Alsace, France
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2009–2011
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French National Centre for Scientific Research
Lyon, Rhone-Alpes, France
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