Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Stéphane Golhen is active.

Publication


Featured researches published by Stéphane Golhen.


Chemistry: A European Journal | 1998

Synthesis and Magnetic Behavior of Rare-Earth Complexes with N,O-Chelating Nitronyl Nitroxide Triazole Ligands: Example of a [GdIII{Organic Radical}2] Compound with anS=9/2 Ground State

Jean-Pascal Sutter; Myrtil L. Kahn; Stéphane Golhen; Lahcène Ouahab; Olivier Kahn

A ferromagnetically coupled gadolinium–radical compound is described. A series of three lanthanide complexes of general formula [Ln(organic radical)2(NO3)3] (Ln =Y3+, La3+, and Gd3+, shown on the right) have been synthesized. With the paramagnetic GdIII a ferromagnetic interaction with the ligands was found, which gives rise to a S = 9/2 ground-state spin.


Angewandte Chemie | 2015

Magnetic Memory in an Isotopically Enriched and Magnetically Isolated Mononuclear Dysprosium Complex

Fabrice Pointillart; Kevin Bernot; Stéphane Golhen; Boris Le Guennic; Thierry Guizouarn; Lahcène Ouahab; Olivier Cador

The influence of nuclear spin on the magnetic hysteresis of a single-molecule is evidenced. Isotopically enriched Dy(III) complexes are synthesized and an isotopic dependence of their magnetic relaxation is observed. This approach is coupled with tuning of the molecular environment through dilution in an amorphous or an isomorphous diamagnetic matrix. The combination of these approaches leads to a dramatic enhancement of the magnetic memory of the molecule. This general recipe can be efficient for rational optimization of single-molecule magnets (SMMs), and provides an important step for their integration into molecule-based devices.


Angewandte Chemie | 1999

A Mixed-Valence and Mixed-Spin Molecular Magnetic Material: [MnIIL]6[MoIII(CN)7][MoIV(CN)8]2⋅19.5 H2O

Amandeep Kaur Sra; Marius Andruh; Olivier Kahn; Stéphane Golhen; Lahcène Ouahab; J. V. Yakhmi

Long-range ferromagnetic ordering at 3 K is observed for the title compound, which may be considered as a fully localized mixed-valence species (Mo(3+) and Mo(4+)) as well as a mixed-spin species (low-spin and high-spin Mn(2+) ions). Its two-dimensional structure consists of heart-shaped 48-membered rings, and each ring contains 16 metal centers (see picture).


Journal of the American Chemical Society | 2013

Magnetic Poles Determinations and Robustness of Memory Effect upon Solubilization in a DyIII-Based Single Ion Magnet

Tamyris T. da Cunha; Julie Jung; Marie Emmanuelle Boulon; Giulio Campo; Fabrice Pointillart; Cynthia L. M. Pereira; Boris Le Guennic; Olivier Cador; Kevin Bernot; Francesco Pineider; Stéphane Golhen; Lahcène Ouahab

The [Dy(tta)3(L)] complex behaves as a single ion magnet both in its crystalline phase and in solution. Experimental and theoretical magnetic anisotropy axes perfectly match and lie along the most electro-negative atoms of the coordination sphere. Both VSM and MCD measurements highlight the robustness of the complex, with persistence of the memory effect even in solution up to 4 K.


Chemistry: A European Journal | 2010

Tetrathiafulvalene-amido-2-pyridine-N-oxide as Efficient Charge-Transfer Antenna Ligand for the Sensitization of YbIII Luminescence in a Series of Lanthanide Paramagnetic Coordination Complexes

Fabrice Pointillart; Thomas Cauchy; Olivier Maury; Yann Le Gal; Stéphane Golhen; Olivier Cador; Lahcène Ouahab

The tetrathiafulvalene-amido-2-pyridine-N-oxide (L) ligand has been employed to coordinate 4f elements. The architecture of the complexes mainly depends on the ionic radii of the lanthanides. Thus, the reaction of L in the same experimental protocol leads to three different molecular structure series. Binuclear [Ln(2)(hfac)(5)(O(2)CPhCl)(L)(3)]·2 H(2)O (hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate anion, O(2)CPhCl(-)=3-chlorobenzoate anion) and mononuclear [Ln(hfac)(3)(L)(2)] complexes were obtained by using rare-earth ions with either large (Ln(III)=Pr, Gd) or small (Ln(III)=Y, Yb) ionic radius, respectively, whereas the use of Tb(III) that possesses an intermediate ionic radius led to the formation of a binuclear complex of formula [Tb(2)(hfac)(4)(O(2)CPhCl)(2)(L)(2)]. Antiferromagnetic interactions have been observed in the three dinuclear compounds by using an extended empirical method. Photophysical properties of the coordination complexes have been studied by solid-state absorption spectroscopy, whereas time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y(III) derivative to build a molecular orbital diagram and to reproduce the absorption spectrum. For the [Yb(hfac)(3)(L)(2)] complex, the excitation at 19,600 cm(-1) of the HOMO→LUMO+1/LUMO+2 charge-transfer transition induces both line-shape emissions in the near-IR spectral range assigned to the (2)F(5/2)→(2)F(7/2) (9860 cm(-1)) ytterbium-centered transition and a residual charge-transfer emission around 13,150 cm(-1). An efficient antenna effect that proceeds through energy transfer from the singlet excited state of the tetrathiafulvalene-amido-2-pyridine-N-oxide chromophore is evidence of the Yb(III) sensitization.


Chemistry: A European Journal | 2011

Single-Molecule Magnet Behaviour in a Tetrathiafulvalene-Based Electroactive Antiferromagnetically Coupled Dinuclear Dysprosium(III) Complex

Fabrice Pointillart; Yann Le Gal; Stéphane Golhen; Olivier Cador; Lahcène Ouahab

The reactions between the [Ln(tta)(3)]·2H(2)O precursors (tta(-)=2-thenoyltrifluoroacetonate anion) and the tetrathiafulvalene-3-pyridine-N-oxide ligands (L(1)) lead to dinuclear complexes of formula [{Ln(tta)(3)(L(1))}(2)]·xCH(2)Cl(2) (x=0.5 for Ln=Dy(III) (1) and x=0 for Ln=Gd(III) (2)). The crystal structure reveals that two {Ln(tta)(3)} moieties are bridged by two donors through the nitroxide groups. The Dy(III) centre adopts a distorted square antiprismatic oxygenated polyhedron structure. The antiferromagnetic nature of the exchange interaction between the two Dy(III) ions has been determined by two methods: 1) an empirical method using the [Dy(hfac)(3)(L(2))(2)] mononuclear complex as a model (3) (hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate anion, L(2)=tetrathiafulvaleneamido-2-pyridine-N-oxide ligand), and 2) assuming an Ising model for the Dy(III) ion giving an exchange energy of -2.30 cm(-1), g=19.2 in the temperature range of 2-10 K. The antiferromagnetic interactions have been confirmed by a quantitative determination of J for the isotropic Gd(III) derivative (J=-0.031 cm(-1), g=2.003). Compound 1 displays a slow magnetisation relaxation without applied external magnetic fields. Alternating current susceptibility shows a thermally activated behaviour with pre-exponential factors of 5.48(4)×10(-7) s and an energy barrier of 87(1) K. The application of an external field of 1.6 kOe compensates the antiferromagnetic interactions and opens a new quantum tunnelling path.


Chemistry: A European Journal | 2008

Delicate Crystal Structure Changes Govern the Magnetic Properties of 1D Coordination Polymers Based on 3d Metal Carboxylates

Konstantin S. Gavrilenko; Olivier Cador; Kevin Bernot; Patrick Rosa; Roberta Sessoli; Stéphane Golhen; Vitaly V. Pavlishchuk; Lahcène Ouahab

Homo- and heterometallic 1D coordination polymers of transition metals (Co II, Mn II, Zn II) have been synthesized by an in-situ ligand generation route. Carboxylato-based complexes [Co(PhCOO)2]n (1 a, 1 b), [Co(p-MePhCOO)2]n (2), [ZnMn(PhCOO)4]n (3), and [CoZn(PhCOO)4]n (4) (PhCOOH=benzoic acid, p-MePhCOOH=p-methylbenzoic acid) have been characterized by chemical analysis, single-crystal X-ray diffraction, and magnetization measurements. The new complexes 2 and 3 crystallize in orthorhombic space groups Pnab and Pcab respectively. Their crystal structures consist of zigzag chains, with alternating M(II) centers in octahedral and tetrahedral positions, which are similar to those of 1 a and 1 b. Compound 4 crystallizes in monoclinic space group P2 1/c and comprises zigzag chains of M II ions in a tetrahedral coordination environment. Magnetic investigations reveal the existence of antiferromagnetic interactions between magnetic centers in the heterometallic complexes 3 and 4, while ferromagnetic interactions operate in homometallic compounds (1 a, 1 b, and 2). Compound 1 b orders ferromagnetically at TC=3.7 K whereas 1 a does not show any magnetic ordering down to 330 mK and displays typical single-chain magnet (SCM) behavior with slowing down of magnetization relaxation below 0.6 K. Single-crystal measurements reveal that the system is easily magnetized in the chain direction for 1 a whereas the chain direction coincides with the hard magnetic axis in 1 b. Despite important similarities, small differences in the molecular and crystal structures of these two compounds lead to this dramatic change in properties.


New Journal of Chemistry | 2000

Hepta/octa cyanomolybdates with Fe2+: influence of the valence state of Mo on the magnetic behavior

Amandeep Kaur Sra; Guillaume Rombaut; Frédéric Lahitête; Stéphane Golhen; L. Ouahab; Corine Mathonière; J. V. Yakhmi

Two FeII-based molybdenum polycyanides, Fe2[MoIII(CN)7]·8H2O and [Fe2(H2O)4][MoIV(CN)8]·4H2O, have been synthesized. The compound [Fe2(H2O)4][MoIV(CN)8]·4H2O crystallizes in the tetragonal system, space group I422. There are two molybdenum sites in a distorted square antiprism arrangement, each site being surrounded by eight CN–Fe linkages. The distorted octahedral iron site is formed by four NC–Mo linkages and two water molecules in apical positions. The structure is three-dimensional and highly symmetrical. The magnetic characteristics of these two compounds were compared. Fe2[MoIII(CN)7]·8H2O orders below 65 K as a ferrimagnet, but [Fe2(H2O)4][MoIV(CN)8]·4H2O shows no evidence of long-range magnetic order, obviously due to the contribution of the diamagnetic MoIV which suppresses the propagation of magnetic interaction between adjacent iron(II) ions through CN bridges. The results are discussed in the light of the single-crystal structural features of [Fe2(H2O)4][MoIV(CN)8]·4H2O.


Inorganica Chimica Acta | 2001

Synthesis, X-ray crystal structures and magnetic properties of Cu(II)(NITpPy)2[N(CN)2]2·solv (NITpPy=nitronyl nitroxide radical, solv=H2O or CH3CN). From discrete molecules to 2-D polymeric coordination compounds

Iwayan Dasna; Stéphane Golhen; Lahcène Ouahab; Mohammed Fettouhi; O. Peña; Nathalie Daro; Jean-Pascal Sutter

Abstract The synthesis, X-ray crystal structures and magnetic properties of five new copper(II) complexes containing nitroxide radicals Cu(NITpPy)2(NO3)2 (1), Cu(NITpPy)2(CH3COO)2 (2), Cu(NITpPy)2[N(CN)2]2·(H2O)2 (3), Cu(NITpPy)2[N(CN)2]2·3CH3CN (4) and Cu(NITpPy)2[N(CN)2]2·2CH3CN (5) are reported. Compounds 1–3 consists of discrete molecules in the solid state, but in compounds 4 and 5 the Cu(NITpPy)22+ units are connected through N(CN)2− bridging ligands in μ2 coordination developing, respectively, into one-dimensional and two-dimensional polymeric networks. For all compounds, the magnetic properties have been investigated and antiferromagnetic interactions dominate at low temperature.


Chemistry: A European Journal | 2013

Slow Magnetic Relaxation in Condensed versus Dispersed Dysprosium(III) Mononuclear Complexes

Goulven Cosquer; Fabrice Pointillart; Stéphane Golhen; Olivier Cador; Lahcène Ouahab

Reaction of the ligands 4,5-bis(propylthio)tetrathiafulvalene-2-(2-pyridyl)benzimidazole (L(1)) and 4,5-bis(propylthio)tetrathiafulvalene-2-(2-pyridyl)-3-(2-pyridinylmethyl)benzimidazole (L(2)) with Dy(hfac)3⋅2 H2O (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate) gave mononuclear complexes [Dy(hfac)3(L(1))] (1) and [Dy(hfac)3(L(2))] (2). In both compounds the Dy(III) ion is surrounded by six oxygen and two nitrogen atoms. Complex 1 displays single-ion magnet (SIM) behaviour only in solution (Δ=12(1) K and τ0 =1.9(4)×10(-6)  s), while complex 2 is a SIM in both solution (Δ=15(2) K and τ0 =1.5(3)×10(-6)  s) and solid state (Δ=17(2) K and τ0 =9.5(2)×10(-6)  s). The SIM behaviour is obtained if the hydrogen bond is broken by dissolution (1 in solution) or by alkylation (2). Multiple relaxation processes were identified for 2 with two competing processes: a fast one in zero field and a slow one for fields higher than 500 Oe. The two processes coexist for intermediate applied magnetic field. Magnetic-dilution and frozen-solution measurements led to the conclusion that the origin of these multiple relaxation processes is not due to the property of a single molecule.

Collaboration


Dive into the Stéphane Golhen's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Olivier Cador

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Boris Le Guennic

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar

Olivier Kahn

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar

Sergey V. Kolotilov

National Academy of Sciences

View shared research outputs
Top Co-Authors

Avatar

L. Ouahab

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge