HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation

Commutation thermo- et photo-induite de solides moléculaires a transition de spin : du monocristal aux nano-objets

Abstract : This work is devoted to synthesis of spin-crossover compounds and to the study of their thermo- or photo-induced switching. Photo-induced spin-crossover, either by the Light-Induced Excited Spin State Trapping (LIESST) or the Ligand Driven Light-Induced Spin Change (LD-LISC)) effects, has been studied in the solid state. The synthesis of spin-crossover nanoparticles built with compounds of molecular nature and the study of their switching properties has then been examined. The synthesis of optimized materials for the study of the photo-switching mechanism (LIESST effect) at ultrafast timescales has been developed and the first time-resolved measurements are presented. The study of the LD-LISC effect on the FeII(stpy)4(NCSe)2 (stpy = 4-styrylpyridine, photo-isomerizable ligand) complexes has also been performed, either bydispersing the compound in a polymeric matrix, or on the crystalline state. Different photo-induced behaviours have been evidenced, depending on the compound environment. On thecrystalline state, a unidirectional reactivity of the stpy ligand through an original mechanism following the excitation in the MLCT excited states has been evidenced. The synthesis of spin-crossover nanoparticles with compounds of molecular nature has then been performed with two different methods. First, the sol-gel process has been used to obtain well dispersed nanoparticles in a silica thin film. This approach allows the synthesis of size-controlled particles trapped on solids of good optical quality, in which a thermo- and photo-induced spin crossover has been observed with the [FeII(mepy)3tren](PF6)2 compound. Another synthetic method, based on the precipitation in an anti-solvent, has been successfully applied to various spin-crossover complexes. With the [FeIII(3-OMeSalEen)2]PF6 compound, size-controlled particles have been prepared and, interestingly, the size reduction effect on the cooperative processes appears to be limited. Finally, the study of FeII(phen)2(NCS)2 microcrystals has evidenced that the interaction between the polymer and the particles can affect their thermo- and photo-induced spin-crossover processes.
Document type :
Complete list of metadata

Cited literature [97 references]  Display  Hide  Download

Contributor : Abes Star :  Contact
Submitted on : Wednesday, February 1, 2012 - 2:37:16 PM
Last modification on : Thursday, December 9, 2021 - 12:52:03 PM
Long-term archiving on: : Wednesday, May 2, 2012 - 2:35:45 AM


Version validated by the jury (STAR)


  • HAL Id : tel-00665234, version 1


Antoine Tissot. Commutation thermo- et photo-induite de solides moléculaires a transition de spin : du monocristal aux nano-objets. Autre. Université Paris Sud - Paris XI, 2011. Français. ⟨NNT : 2011PA112012⟩. ⟨tel-00665234⟩



Record views


Files downloads