A5042957930- Radioactive element chemistry and processing
- Lanthanide and Transition Metal Complexes
- Magnetism in coordination complexes
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advanced Chemical Physics Studies
- Electron Spin Resonance Studies
- Crystallography and molecular interactions
- Animal Nutrition and Physiology
- Metal-Organic Frameworks: Synthesis and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Inorganic Fluorides and Related Compounds
- Nuclear Materials and Properties
- History and advancements in chemistry
- Rabbits: Nutrition, Reproduction, Health
- Radioactive contamination and transfer
- Inorganic Chemistry and Materials
- Chemical Synthesis and Characterization
- Metal complexes synthesis and properties
- Advanced Condensed Matter Physics
- Organic and Molecular Conductors Research
- Radiopharmaceutical Chemistry and Applications
- Advanced Topics in Algebra
- Algebraic structures and combinatorial models
- Molecular spectroscopy and chirality
Centre National de la Recherche Scientifique
2015-2024
Institut des Sciences Chimiques de Rennes
2021-2024
Université de Rennes
2021-2024
Institute of Catalysis and Petrochemistry
2024
Nantes Université
2014-2023
Laboratoire de Physique Subatomique et des Technologies Associées
2014-2023
IMT Atlantique
2017-2023
Institut National de Physique Nucléaire et de Physique des Particules
2017-2023
University of Minnesota
2013-2016
Université Gustave Eiffel
2013-2015
Monometallic Ni(II) and Co(II) complexes with large magnetic anisotropy are studied using correlated wave function based ab initio calculations. Based on the effective Hamiltonian theory, we propose a scheme to extract both parameters of zero-field splitting (ZFS) tensor axes. Contrarily usual theoretical procedure extraction, method presented here determines sign magnitude ZFS in any circumstances. While energy levels provide enough information complexes, additional contained functions must...
The nature and magnitude of the magnetic anisotropy heptacoordinate mononuclear Ni(II) Co(II) complexes were investigated by a combination experiment ab initio calculations. zero-field splitting (ZFS) parameters D [Ni(H(2)DAPBH)(H(2)O)(2)](NO(3))(2)⋅2 H(2)O (1) [Co(H(2)DAPBH)(H(2)O)(NO(3))](NO(3)) [2; H(2)DAPBH = 2,6-diacetylpyridine bis- (benzoyl hydrazone)] determined means magnetization measurements high-field high-frequency EPR spectroscopy. negative value, hence an easy axis...
This paper reports the experimental and theoretical investigations of two trigonal bipyramidal Ni(II) complexes, [Ni(Me(6)tren)Cl](ClO(4)) (1) [Ni(Me(6)tren)Br](Br) (2). High-field, high-frequency electron paramagnetic resonance spectroscopy performed on a single crystal 1 shows giant uniaxial magnetic anisotropy with an D(expt) value (energy difference between M(s) = ± 0 components ground spin state S 1) estimated to be -120 -180 cm(-1). The study that, for ideally complex, orbital...
The zero-field splitting of the copper acetate monohydrate complex is studied using wave function based calculations. anisotropy parameters extracted from highly correlated methods are in excellent agreement with most accurate experimental results; particular, negative sign axial parameter D reproduced. During several decades, interpretation data on an analytical expression derived perturbation theory led to a positive D-value. Although validity this confirmed, it explained that incorrect...
A multidentate ligand platform is introduced that enables the isolation of both homo- and heterobimetallic complexes divalent first-row transition metal ions such as Mn(II), Fe(II), Co(II). By means a two-step metalation strategy, five bimetallic coordination were synthesized with general formula M1M2Cl(py3tren), where py3tren triply deprotonated form N,N,N-tris(2-(2-pyridylamino)ethyl)amine. The metal-metal pairings include dicobalt (1), cobalt-iron (2), cobalt-manganese (3), diiron (4),...
The magnetic anisotropy of the [Ni2(en)4Cl2](2+) (en = ethylenediamine) complex has been studied using wave function based computational schemes. spin-orbit state interaction methodology provides accurate ab initio energies and functions that are used to interpret in bimetallic complexes. extraction anisotropic spin Hamiltonian is performed effective theory. This procedure which successfully applied mononuclear complexes enables one solve weak exchange limit. It shown standard coupled only...
Pentagonal-bipyramidal complexes [Co(DABPH)X(H2O)]X [X = NO3 (1), Br (2), I (3)] were synthesized, and their magnetic behavior was investigated. Simulation of the magnetization versus temperature data revealed to be highly anisotropic (D ≈ +30 cm–1) magnitude anisotropy independent nature axial ligands. The reaction 1 with K3[M(CN)6] (M Cr, Fe) produces pentametallic clusters [{Co(DABPH)}3{M(CN)6}2(H2O)2] [M Cr (4), Fe (5)]. Both consist three {Co(DABPH)} moieties separated by two {M(CN)6}...
By many-body quantum-chemical calculations, we investigate the role of two structural effects - local ligand distortions and anisotropic Cd-ion coordination on magnetic state Cd2Os2O7, a spin S=3/2 pyrochlore. We find that these strongly compete, rendering interactions ordering crucially depend geometrical features. Without trigonal large easy-plane anisotropy develops. Their presence, however, reverses sign zero-field splitting causes easy-axis (D = -6.8 meV), which in conjunction with...
Abstract 211 At is a most promising radionuclide for targeted alpha therapy. However, its limited availability and poorly known basic chemistry hamper use. Based on the analogy with iodine, labelling performed via astatobenzoate conjugates, but in vivo deastatination occurs, particularly when conjugates are internalized cells. Actually, chemical or biological mechanism responsible unknown. In this work, we show that C−At “organometalloid” bond can be cleaved by oxidative dehalogenation...
Abstract It is generally assumed that astatide (At − ) the predominant astatine species in basic aqueous media. This assumption questioned non‐complexing and non‐reductive solutions by means of high‐pressure anion‐exchange chromatography. Contrary to what usually believed, found be a minor at pH=11. A different species, which also bears single negative charge, becomes when pH increased beyond 7. Using competition experiments, an equilibrium constant value 10 −6.9 has been determined for...
The zero-field splitting (ZFS) of a model monometallic Mn(III) complex is theoretically studied as function systematic symmetry lowering. First, we treat the octahedral case for which standard Ŝ⋅D̿⋅Ŝ Hamiltonian cannot be applied due to in absence anisotropy induced by spin-orbit coupling between two spatial components E5g state at second-order perturbation. Next, lowered D4h and D2h anisotropic spin extracted using effective theory. A simple relation derived ratio E/|D| rhombic axial...
The antisymmetric magnetic interaction is studied using correlated wave-function-based calculations in oxo-bridged copper bimetallic complexes. All of the anisotropic multispin Hamiltonian parameters are extracted spin-orbit state and effective theory. It shown that methodology accurate enough to calculate terms, while small symmetric interactions require more sophisticated calculations. origin anisotropy analyzed, effect geometrical deformations addressed.
In benzophenone, intersystem crossing occurs efficiently between the S1(nπ*) state and T1 of dominant nπ* character, leading to excited triplet states after photoexcitation. The transition mechanism is still a matter debate, despite several experimental studies. Quantum mechanical calculations have been performed in order assess relative efficiencies previously proposed mechanisms, particular, direct S1→ indirect T2(ππ*) → ones. Multiconfigurational wave function based methods are used...
The determination of anisotropic magnetic parameters is a task both experimental and theoretical interest. added value calculations can be crucial for analyzing data by (i) allowing assessment the validity phenomenological spin Hamiltonians, (ii) discussion values extracted from experiments, (iii) proposing rationalizations magneto-structural correlations to better understand relations between geometry, electronic structure, properties. In this review, we discuss model Hamiltonians that are...
Carbon dioxide adsorption isotherms have been computed for the metal–organic framework (MOF) Fe2(dobdc), where dobdc4– = 2,5-dioxido-1,4-benzenedicarboxylate. A force field derived from quantum mechanical calculations has used to model within a MOF. Restricted open-shell Møller–Plesset second-order perturbation theory (ROMP2) performed obtain interaction energy curves between CO2 molecule and cluster of Fe2(dobdc). The parameters optimized best reproduced these in Monte Carlo simulations...
The main-group 6p elements did not receive much attention in the development of recent density functionals. In many cases it is still difficult to choose among modern ones a relevant functional for various applications. Here, we illustrate case astatine species (At, Z = 85) and report first, quite complete, benchmark study on several properties concerning such species. Insights geometries, transition energies thermodynamic set 19 species, which reference experimental or theoretical data has...
This work addresses the question of identification excited states that are mainly responsible for magnitude and nature magnetic anisotropy in high-spin mononuclear transition metal complexes. Only few actually single ion anisotropy, these can be anticipated from rather simple rules. We show complexes atomic selection rules still prevail molecular symmetry point group more selective than those double group. The predictive power is exemplified on a penta-coordinate Co(II) complex investigated...
The metal–organic framework Fe2(dobdc) (dobdc4– = 2,5-dioxido-1,4-benzenedicarboxylate), often referred to as Fe-MOF-74, possesses many interesting properties such a high selectivity in olefin/paraffin separations. This compound contains open-shell FeII ions with open coordination sites which may have large single-ion magnetic anisotropies, well isotropic couplings between the nearest and next neighbor sites. To complement previous analysis of experimental data made by considering only...
A systematic study has been undertaken to determine how local distortions affect the overall (molecular) magnetic anisotropies in binuclear complexes. For this purpose we have applied a series of two Ni(II) model complexes and extracted anisotropy parameters multispin giant-spin Hamiltonians. Furthermore, molecular axes frames determined. It is shown that certain combinations can lead constructive interference largest contribution anisotropic exchange does not arise from second-rank tensor...
This paper studies the physical basis of giant-spin Hamiltonian, which is usually used to describe anisotropy single-molecule magnets. A rigorous extraction model has been performed in weak-exchange limit a binuclear centrosymmetric Ni(II) complex, using correlated ab initio calculations and effective Hamiltonian theory. It shown that not appropriate polynuclear complexes as soon spin mixing becomes non-negligible. relevant proposed involving fourth-order operators, different from...
The synthesis of a new NiII–YIII binuclear complex with marked elongation axis in the first coordination sphere NiII ion is presented. Its zero-field splitting (ZFS) studied by means magnetic data and state-of-the-art ab initio calculations. A good agreement between experimental theoretical ZFS parameter values encountered, validating whole approach. anisotropy axes are extracted from calculations, showing that around corresponds to hard magnetization sign axial D imposed this axis. Ni–Y...
The nature of chemical bonds in heavy main-group diatomics is discussed from the viewpoint effective bond orders, which are computed spin-orbit wave functions resulting configuration interaction calculations. reliability relativistic correlated obtained such two-step coupling frameworks assessed by benchmark studies spectroscopic constants with respect to either experimental data, or state-of-the-art fully I2, At2, IO(+), and AtO(+) species considered, differences similarities between...