A5004914582- Magnetism in coordination complexes
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Metal-Catalyzed Oxygenation Mechanisms
- Lanthanide and Transition Metal Complexes
- Hydrogen Storage and Materials
- Metal complexes synthesis and properties
- Porphyrin and Phthalocyanine Chemistry
- Crystallography and molecular interactions
- Electron Spin Resonance Studies
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Boron and Carbon Nanomaterials Research
- Spectroscopy and Quantum Chemical Studies
- Inorganic Chemistry and Materials
- Nanocluster Synthesis and Applications
- Photosynthetic Processes and Mechanisms
- Inorganic Fluorides and Related Compounds
- Advanced Nanomaterials in Catalysis
- Boron Compounds in Chemistry
- Organic and Molecular Conductors Research
- Superconductivity in MgB2 and Alloys
- Photoreceptor and optogenetics research
- Luminescence and Fluorescent Materials
- Crystal Structures and Properties
University of Geneva
2015-2024
HES-SO Genève
2016-2024
Laboratoire de Chimie Physique
2016-2021
Charles Humbert 8
2014-2020
Université de Versailles Saint-Quentin-en-Yvelines
2010
Centre National de la Recherche Scientifique
1999-2010
Université Paris-Sud
2010
Leibniz Institute for Solid State and Materials Research
2010
CEA Grenoble
1999-2006
Laboratoire de Chimie
2006
Ultrafast transient absorption spectroscopy serves to identify the (3)dd state as intermediate quencher of (3)MLCT luminescence in non-luminescent ruthenium complexes [Ru(m-bpy)3](2+) (m-bpy = 6-methyl-2,2'-bipyridine) and [Ru(tm-bpy)3](2+) (tm-bpy 4,4',6,6'-tetramethyl-2',2'-bipyridine). For [Ru(m-bpy)3](2+), population from occurs within 1.6 ps, while return ground takes 450 ps. [Ru(tm-bpy)3](2+), corresponding values are 0.16 7.5 respectively. According DFT calculations, methyl groups...
Highly accurate estimates of the high-spin/low-spin energy difference ΔEHLel in high-spin complexes [Fe(NCH)6]2+ and [Co(NCH)6]2+ have been obtained from results CCSD(T) calculations extrapolated to complete basis set limit. These are shown be strongly influenced by scalar relativistic effects. They used assess performances CASPT2 method 30 density functionals GGA, meta-GGA, global hybrid, RSH, double-hybrid types. For method, assessment support proposal [Kepenekian, M.; Robert, V.; Le...
We propose a simple method for predicting the spin state of homoleptic complexes Fe(II) d6 ion with chelating diimine ligands. The approach is based on analysis single metric parameter within free (noncoordinated) ligand: interatomic separation between N-donor metal-binding sites. An extensive existing allows determination critical N···N distances that dictate regions stability high-spin and low-spin complexes, as well intermediate range in which magnetic bistability (spin crossover) can be...
A comparison of density functionals is made for the calculation energy and geometry differences high- [(5)T(2g): (t(2g))(4)(e(g))(2)] low- [(1)A(1g): (t(2g))(6)(e(g))(0)] spin states hexaquoferrous cation [Fe(H(2)O)(6)](2+). Since very little experimental results are available (except crystal structures involving in its high-spin state), primary with our own complete active-space self-consistent field (CASSCF), second-order perturbation theory-corrected (CASPT2), spectroscopy-oriented...
In the iron(II) low-spin complex [Fe(bpy)3]2+, zero-point energy difference between 5T2g(t4(2g)e2g) high-spin and 1A(1g)(t(6)2g) states, Delta(E)0HL, is estimated to lie in range of 2500-5000 cm(-1). This estimate based on low-temperature dynamics high-spin-->low-spin relaxation following light-induced population state assumption that bond-length two states Delta(r)HL equal average value approximately 0.2 A, as found experimentally for spin-crossover system. Calculations density functional...
The ability of different density functionals to describe the structural and energy differences between high- [(5)T(2g):(t(2g))(4)(e(g))(2)] low- [(1)A(1g):(t(2g))(6)(e(g))(0)] spin states small octahedral ferrous compounds is studied. This work an extension our previous study hexaquoferrous cation, [Fe(H(2)O)(6)](2+), [J. Chem. Phys. 120, 9473 (2004)] include a second compound-namely, hexaminoferrous [Fe(NH(3))(6)](2+)-and several additional functionals. In particular, present includes...
Photoswitching of the dielectric constant has been observed for first time in spin-crossover complex [Fe(L)(CN)2]⋅H2O (L=2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene, see picture). The electrical detection a photoinduced change spin state could allow use such complexes optical information-storage devices.
The influence of solute-solvent interactions on the vibrational energy relaxation dynamics perylene and substituted perylenes in first singlet excited-state upon excitation with moderate (<0.4 eV) excess has been investigated by monitoring early narrowing their fluorescence spectrum. This was found to occur timescales ranging from a few hundreds femtoseconds picoseconds. Other processes, such as partial decay anisotropy damping low-frequency oscillation due propagation wavepacket, were take...
Even flow: Photoinduced symmetry-breaking charge separation takes place in a few picoseconds 1,3-bis(perylene)propane dyad polar solvents. Polarized transient absorption measurements show that the direction of flow is random and entirely governed by fluctuations solvent orientation around dyad.
TRIR spectroscopy identifies the low-energy ligand-field state in relaxation cascade for ruthenium(<sc>ii</sc>) polypyridyl complexes.
Hofmann coordination polymers (CPs) that couple the well-studied spin transition of FeII central ion with electron-responsive ligands provide an innovative strategy toward multifunctional metal-organic frameworks (MOFs). Here, we developed a 2D planar network consisting metal-cyanide-metal sheets in unusual mode, brought about by infinitely π-stacked redox-active bipyridinium derivatives as axial ligands. The obtained family materials show vivid thermochromism attributed to electron transfer...
The mechanism of the photoinduced low-spin → high-spin spin crossover is actively being investigated in Fe(II) complexes solution using ultrafast spectroscopies. These studies accurately inform on reaction coordinate chromophore upon photoexcitation. However, they leave open questions regarding role solvent. Here, we report description from a fully ab initio molecular dynamics study structure [Fe(bpy)3]2+ water and organization its solvation shell states. In particular, change states shown...
Four novel bimetallic borohydrides have been discovered, K2M(BH4)4 (M = Mg or Mn), K3Mg(BH4)5, and KMn(BH4)3, are carefully investigated structurally as well regarding their decomposition reaction mechanism by means of in situ synchrotron radiation powder X-ray diffraction (SR-PXD), vibrational spectroscopies (Raman IR), thermal analysis (TGA DTA), ab initio density functional theory (DFT) calculations. Mechano-chemical synthesis (ball-milling) using the reactants KBH4, α-Mg(BH4)2,...
Abstract The new double‐cation Al–Li–borohydride is an attractive candidate material for hydrogen storage due to a very low desorption temperature (∼70 °C) combined with high density (17.2 wt %). It was synthesised by high‐energy ball milling of AlCl 3 and LiBH 4 . structure the compound determined from image‐plate synchrotron powder diffraction supported DFT calculations. shows unique 3D framework within borohydrides (space group= P ‐43 n, =11.3640(3) Å). unexpected composition Al Li (BH )...
The location of the Pd atoms in Pd<sub>2</sub>Au<sub>36</sub>(SC<sub>2</sub>H<sub>4</sub>Ph)<sub>24</sub>, is studied both experimentally and theoretically.
Abstract Electrochemical and photophysical analysis of new donor–acceptor systems 2 3 , in which a benzothiadiazole (BTD) unit is covalently linked to tetrathiafulvalene (TTF) core, have verified that the lowest excited state can be ascribed an intramolecular‐charge‐transfer (ICT) π(TTF)→π*(benzothiadiazole) transition. Owing better overlap HOMO LUMO fused scaffold compound intensity 1 ICT band substantially higher compared . The corresponding CT fluorescence also observed both cases....
In this article, the synthesis of a novel high-conjugated ligand and its corresponding Ru(II) complex PTFTF:Ru is reported, along with linear nonlinear optical characterizations. Two-photon absorption based power limiting properties (OPL), especially in near infrared, are described compared to those analogous complexes previously published. Combined preliminary theoretical approach, allows us highlight several key parameters for OPL optimization such molecular systems more particularly...
For numerous spin crossover complexes, the anisotropic distortion of first coordination shell around transition metal center governs dynamics high-spin/low-spin interconversion. However, this structural parameter remains elusive for samples that cannot be investigated with crystallography. The present work demonstrates how picosecond X-ray absorption spectroscopy is able to capture specific deformation in photoinduced high-spin state solvated [Fe(terpy)2]2+, a complex which belongs prominent...
A bidentate chiral dithiol (diBINAS) is utilised to bridge Au25 nanoclusters form oligomers. Separation by size allows the isolation of fractions that are stable thanks nature linker. The structure products elucidated small-angle X-ray scattering and calculated using density functional theory. Additional structural details studied diffusion-ordered nuclear magnetic resonance spectroscopy, transmission electron microscopy matrix-assisted laser desorption/ionization time flight mass...
Metalloporphyrins with open d-shell ions can drive biochemical energy cycles. However, their utilization in photoconversion is hampered by rapid deactivation. Mapping the relaxation pathways essential for elaborating strategies that favorably alter charge dynamics through chemical design and photoexcitation conditions. Here, we combine transient optical absorption spectroscopy X-ray emission femtosecond resolution to probe directly coupled electronic spin within a photoexcited nickel...
Abstract We report the thermodynamic stabilities and intrinsic strengths of three‐center‐two‐electron B−B−B B−H b −B bonds ( : bridging hydrogen), two‐center‐two‐electron t terminal hydrogen) which can be served as a new, effective tool to determine decisive role intermediates hydrogenation/dehydrogenation reactions borohydride. The calculated heats formation were obtained with G4 composite method B−B−B, −B, derived from local stretching force constants at B3LYP‐D2/cc‐pVTZ level theory for...
State-of-the-art generalized gradient approximation (GGA) (PBE, OPBE, RPBE, OLYP, and HCTH), meta-GGA (VSXC TPSS), hybrid (B3LYP, B3LYP*, O3LYP, PBE0) functionals are compared for the determination of structure energetics D3 [Co(bpy)3](2+) complex in (4)A2 (4)E trigonal components high-spin (4)T1g([Formula: see text] [Formula: ) state low-spin (2)E octahedral (2)Eg([Formula: parentage. Their comparison extends also to investigation Jahn-Teller instability through characterization extrema C2...