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Francoise Robin-Le Guen - One of the best experts on this subject based on the ideXlab platform.
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Emission properties of Diazines chromophores: Structure-properties relationship
Journal of Photochemistry and Photobiology A: Chemistry, 2017Co-Authors: Sylvain Achelle, Francoise Robin-Le GuenAbstract:This article presents the photophysical properties of a series of diazine chromophores. The influence of five parameters has been studied: the presence of a diazine/benzodiazine fragment, the nature of the diazine fragment (1,3-diazine/1,4-diazine), the presence or not of an vinyl linker between diazine ring and phenylene fragments of the π-conjugated bridge, the presence of a phenylene/biphenylene linker and the nature of electron donating group (dimethylamino/diphenylamino). Taguchi's design of experiment combined with analysis of variance methodologies have been employed to highlight the main structural parameters influencing the position of absorption and emission maxima of dichloromethane solution and the extend of emission solvatochromic range exhibited by this family of chromophores. © 2017 Elsevier B.V.
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Dipicolylamine styryldiazine derivatives: Synthesis and photophysical studies
Dyes and Pigments, 2015Co-Authors: Sylvain Achelle, Julian Rodriguez-Lopez, Filip Bureš, Francoise Robin-Le GuenAbstract:Different D-π-A push-pull mols. in which dipicolylamine (DPA) is used as the donor group, different Diazines as the acceptor groups, and styryl as the π-conjugated spacer have been synthesized in a straightforward manner by aldol condensation of 4-(di-2-picolylamino)benzaldehyde and the appropriate methyldiazine. All of the compds. showed π-π* transitions in the UV or visible region and the emission of yellow-green light upon irradn. Significant red shifts were obsd. in the fluorescence emission maxima of these compds. on increasing the solvent polarity, a finding that suggests the formation of an intramol. charge-sepd. emitting state that is also supported by semi-empirical calcns. In some cases, protonation led to marked color changes, thus showing the ability of these mols. to function as colorimetric pH sensors. The DPA and diazine units can act as coordination sites for metal cations such as Zn2+, Cd2+ or Hg2+, leading to a blue or red shift in the fluorescence spectra due to the change in the intramol. charge transfer properties. This phenomenon could become a powerful tool for the creation of multiple emission colors with a single mol. after suitable design.
Sylvain Achelle - One of the best experts on this subject based on the ideXlab platform.
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Emission properties of Diazines chromophores: Structure-properties relationship
Journal of Photochemistry and Photobiology A: Chemistry, 2017Co-Authors: Sylvain Achelle, Françoise Robin-le GuenAbstract:Abstract This article presents the photophysical properties of a series of diazine chromophores. The influence of five parameters has been studied: the presence of a diazine/benzodiazine fragment, the nature of the diazine fragment (1,3-diazine/1,4-diazine), the presence or not of an vinyl linker between diazine ring and phenylene fragments of the π-conjugated bridge, the presence of a phenylene/biphenylene linker and the nature of electron donating group (dimethylamino/diphenylamino). Taguchi's design of experiment combined with analysis of variance methodologies have been employed to highlight the main structural parameters influencing the position of absorption and emission maxima of dichloromethane solution and the extend of emission solvatochromic range exhibited by this family of chromophores.
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Emission properties of Diazines chromophores: Structure-properties relationship
Journal of Photochemistry and Photobiology A: Chemistry, 2017Co-Authors: Sylvain Achelle, Francoise Robin-Le GuenAbstract:This article presents the photophysical properties of a series of diazine chromophores. The influence of five parameters has been studied: the presence of a diazine/benzodiazine fragment, the nature of the diazine fragment (1,3-diazine/1,4-diazine), the presence or not of an vinyl linker between diazine ring and phenylene fragments of the π-conjugated bridge, the presence of a phenylene/biphenylene linker and the nature of electron donating group (dimethylamino/diphenylamino). Taguchi's design of experiment combined with analysis of variance methodologies have been employed to highlight the main structural parameters influencing the position of absorption and emission maxima of dichloromethane solution and the extend of emission solvatochromic range exhibited by this family of chromophores. © 2017 Elsevier B.V.
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Dipicolylamine styryldiazine derivatives: Synthesis and photophysical studies
Dyes and Pigments, 2015Co-Authors: Sylvain Achelle, Julian Rodriguez-Lopez, Filip Bureš, Francoise Robin-Le GuenAbstract:Different D-π-A push-pull mols. in which dipicolylamine (DPA) is used as the donor group, different Diazines as the acceptor groups, and styryl as the π-conjugated spacer have been synthesized in a straightforward manner by aldol condensation of 4-(di-2-picolylamino)benzaldehyde and the appropriate methyldiazine. All of the compds. showed π-π* transitions in the UV or visible region and the emission of yellow-green light upon irradn. Significant red shifts were obsd. in the fluorescence emission maxima of these compds. on increasing the solvent polarity, a finding that suggests the formation of an intramol. charge-sepd. emitting state that is also supported by semi-empirical calcns. In some cases, protonation led to marked color changes, thus showing the ability of these mols. to function as colorimetric pH sensors. The DPA and diazine units can act as coordination sites for metal cations such as Zn2+, Cd2+ or Hg2+, leading to a blue or red shift in the fluorescence spectra due to the change in the intramol. charge transfer properties. This phenomenon could become a powerful tool for the creation of multiple emission colors with a single mol. after suitable design.
Monica Panigati - One of the best experts on this subject based on the ideXlab platform.
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Luminescent dinuclear rhenium(I) complexes containing bridging 1,2-diazine ligands: Photophysical properties and application
Coordination Chemistry Reviews, 2012Co-Authors: Monica Panigati, Matteo Mauro, Daniela Donghi, Pierluigi Mercandelli, Patrizia Romana Mussini, Luisa De Cola, Giuseppe AlfonsoAbstract:Abstract In this contribution we provide an overview of the preparation and of the properties of different classes of luminescent dinuclear tricarbonyl rhenium(I) complexes of general formula [Re 2 (μ-X) 2 (CO) 6 (μ-1,2-diazine)] (X = halide, hydride, alkoxide, and thiolate). Their electrochemical and photophysical properties in solution are presented, as well as combined density functional (DFT) and time-dependent density functional (TDDFT) studies of their geometry, relative stability and electronic structure. The relationships between the structure and the emission properties of the complexes are discussed in detail, showing a modulation effect of the bridging ancillary ligands as well as of the diazine substituents on energy, lifetime and quantum yield of the emission. Photoluminescent quantum yields ( Φ ) up to 0.53 have been measured in fluid solution for the dichloro complexes containing Diazines bearing alkyl groups in both the β positions, designed to optimize all the parameters responsible for the radiative decay. The photophysical properties in the solid state are also briefly presented, showing in some cases an increase of the emission intensity, discussed in terms of restriction of intramolecular roto-vibrational motions. These properties, together with their good processability and high stability, allowed the successful use of some of these complexes as a phosphorescent dopant in OLEDs. The good performances of OLED devices prepared both by solution- and vacuum-processing are reported. The preliminary work exploring the potential of these complexes as luminescent labels for bioimaging is also presented.
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Luminescent dinuclear rhenium(I) complexes contain ing bridging 1,2-diazine ligands : photophysical properties and application
'Elsevier BV', 2012Co-Authors: Monica Panigati, Daniela Donghi, Pierluigi Mercandelli, Patrizia Romana Mussini, Luisa De Cola, M. Mauro, G. D’Abstract:In this contribution we provide an overview of the preparation and of the properties of different classes of luminescentdinuclear tricarbonyl rhenium(I) complexes of general formula [Re2(\u3bc-X)2(CO)6(\u3bc-1,2-diazine)] (X = halide, hydride, alkoxide, and thiolate). Their electrochemical and photophysical properties in solution are presented, as well as combined density functional (DFT) and time-dependent density functional (TDDFT) studies of their geometry, relative stability and electronic structure. The relationships between the structure and the emission properties of the complexes are discussed in detail, showing a modulation effect of the bridging ancillary ligands as well as of the diazine substituents on energy, lifetime and quantum yield of the emission. Photoluminescent quantum yields (\u3a6) up to 0.53 have been measured in fluid solution for the dichloro complexes containing Diazines bearing alkyl groups in both the \u3b2 positions, designed to optimize all the parameters responsible for the radiative decay. The photophysical properties in the solid state are also briefly presented, showing in some cases an increase of the emission intensity, discussed in terms of restriction of intramolecular roto-vibrational motions. These properties, together with their good processability and high stability, allowed the successful use of some of these complexes as a phosphorescent dopant in OLEDs. The good performances of OLED devices prepared both by solution- and vacuum-processing are reported. The preliminary work exploring the potential of these complexes as luminescent labels for bioimaging is also presented
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Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices
Advanced Functional Materials, 2009Co-Authors: Matteo Mauro, Elsa Quartapelle Procopio, Monica Panigati, Daniela Donghi, Chen-han Chien, Pierluigi Mercandelli, Patrizia Romana Mussini, Giuseppe Alfonso, Luisa De ColaAbstract:A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) is reported. These compounds, of general formula [Re2(m-Cl)2(CO)6(m-1,2-diazine)], contain Diazines bearing alkyl groups in one or in both the b positions. Their electrochemical and photophysical properties are presented, as well as a combined density functional and time-dependent density functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess high emission quantum yields (f=0.18–0.22 for the derivatives with disubstituted Diazines). In butyronitrile glass, at 77K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is observed, accompanied by a strong increase in the lifetime values. The highest-performing emitting complex, containing cyclopentapyridazine as ligand, is tested in a polymer-based lightemitting device, with poly(9-vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7bis(diphenylphosphine oxide)-9-(9-phenylcarbazol-3-yl)-9-phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is solution processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes.
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Photoluminescent and crystal structure properties of the yellow and orange forms of [Re2(m-Cl)2(CO)6(m- 4,5-trimethyl-silyl-pyridazine]
2009Co-Authors: Quartapelle E. Procopio, Monica Panigati, Daniela Donghi, Pierluigi Mercandelli, M. Mauro, G. D’, A.a.d. Sironi, Luisa De ColaAbstract:A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) has been recently reported1,2. These compounds, of general formula [Re2(\u3bc-Cl)2(CO)6(\u3bc-1,2-diazine)], contain Diazines bearing alkyl groups in one or in both the b positions. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess, in solution, high emission quantum yields (F 0.18-0.22 for the derivatives with disubstituted Diazines). The excited state responsible for this emission can be confidentially described as a triplet metal-to-ligand charge transfer (3MLCT) level3. Following the DFT computational suggestions we have now synthetized a new complex of this family using the 4,5-bis(trimetylsilyl)-1,2-diazine ligand namely [Re2(m-Cl)2(CO)6(m- 4,5-trimethyl-silyl-pyridazine] (1, see Scheme). This complex has been completely carachterized in solution and it shows an emission maximum batochromically shifted respect to those of the analogous Re(I) compounds with alkyl-substituted diazine, with a lower quantum yield. Slow evaporation at room temperature of a CH2Cl2 solution containing (1) induces the concomitant formation of orange and yellow single crystals (Figure 1, top). X-ray crystal structure determinations performed at room temperature as well as at 100 K, show that they are two different polymorphs of the same compound. The emission spectra recorded on crystalline samples of the two polymorph (Figure 1, bottom) are hypsochromically shifted respect to the solution one and present higher quantum yields (lem = 537 nm and F = 0.30 for the yellow phase, lem = 575 nm and F = 0.50, for the orange one). References (1) Mauro, M, Quartapelle Procopio, E., Sun,Y., Chien, C-H., Donghi, D., Panicati, M., Mercandelli, P., Mussini, P., D\u2019Alfonso, G., De Cola, L. Adv. Func. Mat. 2009, in press (2) Donghi, D., D\u2019Alfonso, G., Mauro, M, Panigati, M., Mercandelli, P., Sironi, A., Mussini, P., D\u2019Alfonso, L., Inorg. Chem. 2008, 47, 4243. (3) Wrighton, M., Morse, D. L., J. Am. Chem. Soc., 1974, 96, 998
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Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices
'Wiley', 2009Co-Authors: M. Mauro, Monica Panigati, Daniela Donghi, Chen-han Chien, Pierluigi Mercandelli, Patrizia Romana Mussini, Quartapelle E. Procopio, Y. Sun, G. D&apos, Luisa De ColaAbstract:A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent org. light emitting devices (OLEDs) is reported. These compds., of general formula [Re2(\uf06d-Cl)2(CO)6(\uf06d-1,2-diazine)], contain Diazines bearing alkyl groups in one or in both the \uf062 positions. Their electrochem. and photophys. properties are presented, as well as a combined d. functional and time-dependent d. functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene soln. and in the solid state and some of the complexes possess high emission quantum yields (\uf066 = 0.18-0.22 for the derivs. with disubstituted Diazines). In butyronitrile glass, at 77 K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is obsd., accompanied by a strong increase in the lifetime values. The highest-performing emitting complex, contg. cyclopentapyridazine as ligand, is tested in a polymer-based light-emitting device, with poly(9-vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7-bis(diphenylphosphine oxide)-9-(9-phenylcarbazol-3-yl)-9-phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is soln. processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes
Giuseppe Alfonso - One of the best experts on this subject based on the ideXlab platform.
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Luminescent dinuclear rhenium(I) complexes containing bridging 1,2-diazine ligands: Photophysical properties and application
Coordination Chemistry Reviews, 2012Co-Authors: Monica Panigati, Matteo Mauro, Daniela Donghi, Pierluigi Mercandelli, Patrizia Romana Mussini, Luisa De Cola, Giuseppe AlfonsoAbstract:Abstract In this contribution we provide an overview of the preparation and of the properties of different classes of luminescent dinuclear tricarbonyl rhenium(I) complexes of general formula [Re 2 (μ-X) 2 (CO) 6 (μ-1,2-diazine)] (X = halide, hydride, alkoxide, and thiolate). Their electrochemical and photophysical properties in solution are presented, as well as combined density functional (DFT) and time-dependent density functional (TDDFT) studies of their geometry, relative stability and electronic structure. The relationships between the structure and the emission properties of the complexes are discussed in detail, showing a modulation effect of the bridging ancillary ligands as well as of the diazine substituents on energy, lifetime and quantum yield of the emission. Photoluminescent quantum yields ( Φ ) up to 0.53 have been measured in fluid solution for the dichloro complexes containing Diazines bearing alkyl groups in both the β positions, designed to optimize all the parameters responsible for the radiative decay. The photophysical properties in the solid state are also briefly presented, showing in some cases an increase of the emission intensity, discussed in terms of restriction of intramolecular roto-vibrational motions. These properties, together with their good processability and high stability, allowed the successful use of some of these complexes as a phosphorescent dopant in OLEDs. The good performances of OLED devices prepared both by solution- and vacuum-processing are reported. The preliminary work exploring the potential of these complexes as luminescent labels for bioimaging is also presented.
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Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices
Advanced Functional Materials, 2009Co-Authors: Matteo Mauro, Elsa Quartapelle Procopio, Monica Panigati, Daniela Donghi, Chen-han Chien, Pierluigi Mercandelli, Patrizia Romana Mussini, Giuseppe Alfonso, Luisa De ColaAbstract:A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) is reported. These compounds, of general formula [Re2(m-Cl)2(CO)6(m-1,2-diazine)], contain Diazines bearing alkyl groups in one or in both the b positions. Their electrochemical and photophysical properties are presented, as well as a combined density functional and time-dependent density functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess high emission quantum yields (f=0.18–0.22 for the derivatives with disubstituted Diazines). In butyronitrile glass, at 77K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is observed, accompanied by a strong increase in the lifetime values. The highest-performing emitting complex, containing cyclopentapyridazine as ligand, is tested in a polymer-based lightemitting device, with poly(9-vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7bis(diphenylphosphine oxide)-9-(9-phenylcarbazol-3-yl)-9-phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is solution processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes.
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Competition studies on the activation of the C-H bond of Diazines by the unsaturated triangular cluster anion [Re3(μ-H) 4(CO)10]
Journal of Molecular Catalysis A-chemical, 2003Co-Authors: Tiziana Beringhelli, Monica Panigati, Pierluigi Mercandelli, Giuseppe Alfonso, Daniela Maggioni, Angelo SironiAbstract:Abstract The reactions of the unsaturated cluster anion [Re3(μ-H)4(CO)10]− (1) with 1,2-, 1,3- and 1,4-Diazines (used as solvents) have been investigated. The reaction with 1,2-diazine at room temperature gives quantitatively the anion [Re3(μ-H)2(μ-η2-N2C4H4)(CO)10]− (3), containing a diazine bridging through the two N atoms, characterised by single crystal X-ray analysis. The orthometallated isomer [Re3(μ-H)3(μ-η2-N2C4H3)(CO)10]− (4) was obtained by refluxing 3 in toluene. The reaction of [NEt4]1 in molten 1,4-diazine (60 °C) affords the anion [Re3(μ-H)3(μ-η2-N2C4H3)(CO)10]− (5), containing orthometallated pyrazine. The slow reaction of [NEt4]1 with 1,3-diazine at room temperature gives two orthometallated isomers 6, corresponding to the metallation of carbon C2 (6a) and C6 (6b), respectively (6b/6a ratio ca. 1.2). Differently from what previously found for the analogous cluster anion containing orthometallated pyridine, the metallation reaction of Diazines showed little reversibility, and poor conversion of 5 and 6 to the starting anion 1 was observed after several days under 100 atm of H2. Competition experiments, performed by dissolving [NEt4]1 in equimolar mixtures of pyridine/pyrazine or pyridine/pyrimidine, showed that the anion with metallated pyridine was the kinetically preferred product and that at longer times it slowly converted to the derivatives with metallated Diazines (5 or 6).
Jean-pierre Majoral - One of the best experts on this subject based on the ideXlab platform.
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Intramolecular Cyclization of Dinitriles via Zirconocene(IV)−Phosphorus Exchange Reactions: Synthesis of σ3,λ3-1-Phospha- and σ3,λ3-1,4-Diphospha-2,6-Diazines
Organometallics, 1999Co-Authors: Alexandrine Maraval, And Alain Igau, Bruno Donnadieu, Jean-pierre MajoralAbstract:Dinitrile cyclization reactions leading to new six-membered heterocycles 1-σ3,λ3-phospha-2,6-Diazines 3a,b and 1,4-σ3,λ3-diphospha-2,6-Diazines 6, 7, and 8 are presented. These syntheses involve dinitrile derivatives, Schwartz reagent [Cp2ZrHCl]n, and phosphorus compounds as promoted cyclization reagents. An X-ray crystal structure of the 1,4-σ3,λ3-diphospha-2,6-diazine 8 is reported.
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Phosphorus Compounds as Cyclization Promoted Reagents: Preparation of 1,4-α3,γ3-Diphospha-2,6-Diazines
Phosphorus Sulfur and Silicon and the Related Elements, 1999Co-Authors: And Alain Igau, Alexandrine Maraval, Jean-pierre MajoralAbstract:Abstract lmines are important classes of compounds in chemistry. In our continued investigation in the studies of the interactions betwcen group 4 (Zr, Ti) elements and main group elements we recently developped a new methodology for the preparation of various σ3, λ3 phospha-imines. Extension of this work allowed us to prepare unprecedented 8-π electron 6-membered phosphorus heterocycles; 1, 4 σ3, λ3 diphospha-2,6-Diazines. The formation of these Diazines involved for the first time the use of phosphorus derivatives as cyclization promoted reagents in zirconocene chemistry.