0000000000116090

AUTHOR

David Casanova

0000-0002-8893-7089

showing 4 related works from this author

Breaking Bonds and Forming Nanographene Diradicals with Pressure.

2017

New anthanthrone-based polycyclic scaffolds possessing peripheral crowed quinodimethanes have been prepared. While the compounds adopt a closed-shell butterfly shaped structure in the ground state, a concave-to-convex fluxional dynamic inversion is accessible with a low energy barrier through an open-shell diradicaloid transition-state. Mainly driven by the release of strainattributed to the steric hindrance at the peri position of the anthanthrone core, a low-lying open-shell diradical is accessible through planarization of the core, which can be achieved by thermal excitation in solution. Alternatively, planarization can be achieved by application of mild pressure in the solid state, in w…

Steric effects010405 organic chemistryDiradicalSolid-stateGeneral MedicineGeneral Chemistry010402 general chemistryPhotochemistry01 natural sciencesQuantum chemistryCatalysis3. Good health0104 chemical scienceschemistry.chemical_compoundsymbols.namesakeAnthanthronechemistryChemical-mechanical planarizationsymbolsRaman spectroscopyGround stateAngewandte Chemie (International ed. in English)
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High Yield Ultrafast Intramolecular Singlet Exciton Fission in a Quinoidal Bithiophene

2015

We report the process of singlet exciton fission with high-yield upon photoexcitation of a quinoidal thiophene molecule. Efficient ultrafast triplet photogeneration and its yield are determined by photoinduced triplet-triplet absorption, flash photolysis triplet lifetime measurements, as well as by femtosecond time-resolved transient absorption and fluorescence methods. These experiments show that optically excited quinoidal bithiophene molecule undergoes ultrafast formation of the triplet-like state with the lifetime ∼57 μs. CASPT2 and RAS-SF calculations have been performed to support the experimental findings. To date, high singlet fission rates have been reported for crystalline and pol…

FissionChemistryQuantum yieldPhotochemistryPhotoexcitationCondensed Matter::Materials ScienceIntramolecular forceExcited stateSinglet fissionUltrafast laser spectroscopyFlash photolysisGeneral Materials SciencePhysics::Chemical PhysicsPhysical and Theoretical ChemistryThe Journal of Physical Chemistry Letters
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Fluoreno[2,1-a]fluorene: an ortho-naphthoquinodimethane-based system with partial diradical character.

2019

Fluoreno[2,1-a]fluorene, a molecule comprising fused ortho-quinodimethane units in a 1,5-napthoquinodimethane core, has been prepared and investigated with spectroscopy (UV-Vis-NIR, 1H-NMR and Raman), SQUID magnetometry, spectroelectrochemistry and quantum chemistry. While para-quinodimethanes with a 2,6-substitution pattern exist as closed-shell species and meta-quinodimethanes with 2,7-substitution favour a ground electronic state with very large diradical character, our 1,5-substituted ortho-naphthoquinodimethane-based system exhibits an intermediate degree of diradical character.

Materials scienceFluorene010402 general chemistry01 natural sciencesQuantum chemistryCatalysischemistry.chemical_compoundsymbols.namesakebiology.animalMaterials ChemistryMoleculeSpectroscopySquidbiology010405 organic chemistryDiradicalMetals and AlloysGeneral Chemistry0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsCrystallographyCharacter (mathematics)chemistryCeramics and CompositessymbolsRaman spectroscopyChemical communications (Cambridge, England)
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CCDC 1542456: Experimental Crystal Structure Determination

2018

Related Article: Maude Desroches, Paula Mayorga Burrezo, Joël Boismenu-Lavoie, Miriam Peña Álvarez, Carlos J. Gómez-García, Jon M. Matxain, David Casanova, Jean-François Morin, Juan Casado|2017|Angew.Chem.,Int.Ed.|56|16212|doi:10.1002/anie.201708740

Space GroupCrystallography44'4''4'''-[(410-bis{[tris(propan-2-yl)silyl]ethynyl}naphtho[78123-nopqr]tetraphene-612-diylidene)dimethanediylylidene]tetrabenzonitrile chloroform solvateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
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