3d and 4d coordination complexes and coordination polymers involving electroactive tetrathiafulvalene containing ligands

International audienceThe "through bond" approach has been recently developed to increase the interaction between the mobile π and localized d electrons in multifunctional molecular materials involving tetrathiafulvalene-based ligands. This article reviews the 3d and 4d coordination complexes and polymers elaborated from a library of tetrathiafulvalene derivatives containing ligands obtained recently in our group. The different synthetic ways of the complexes are highlighted as well as their chemical and physical properties

Redox-Active Dysprosium Single-Molecule Magnet: Spectro-Electrochemistry and Theoretical Investigations

International audienc

A new approach towards ferromagnetic conducting materials based on TTF-containing polynuclear complexes

International audienceFive complexes containing binuclear cation [Cu2(LH)2]2+ (LH2 = 1 : 2 Schiff base of 1,3-diaminobenzene and butanedione monoxime) were prepared and characterized. Metathesis of one perchlorate anion in [Cu2(LH)2(H2O)2](ClO4)2 (1) by anionic TTF-carboxylate (TTF-CO2−) leads to the complex [Cu2(LH)2(CH3OH)2](TTF-CO2)(ClO4)*H2O (2). Reactions of 1 with substituted pyridines bipy, dpe and TTF-CH = CH-py result in formation of the complexes {[Cu2(LH)2(bipy)](ClO4)2}n*2nH2O (3), [Cu2(LH)2(dpe)2](ClO4)2*2CH3OH (4) and [Cu2(LH)2(TTF-CH = CH-py)(H2O)](ClO4)2*1.5H2O (5), where bipy = 4,4′-bipyridine, dpe = trans-(4-pyridyl)-1,2-ethylene and TTF-CH = CH-py = 1-(2-tetrathiafulvalenyl)-2-(4-pyridyl)ethylene. Whereas complex 2 is built from discrete ionic particles (with rather long Cu-S contacts), compounds 1 and 3 contain 1D polymeric chains, in which structural units are bonded through Cu-O bonds or through bridging bipy molecule, respectively. Dinuclear complexes 4 and 5 are linked though π-stacking of dpe or TTF-CH = CH-py, respectively. All complexes are characterized by dominating ferromagnetic behavior with J values in the range from +9.92(8) cm−1 to +13.4(2) cm−1 for Hamiltonian H = -JS1S2. Magnetic properties of the compounds, containing stacks of aromatic molecules in crystal structures (4 and 5), correspond to ferromagnetic intradimer and antiferromagnetic intermolecular interactions (zJ′ = −0.158(3) and −0.290(2) cm−1, respectively). It was found that TTF-CH = CH-py ligand in [Cu2(LH)2(TTF-CH = CH-py)(H2O)]2+ could be electrochemically oxidized to cation-radical form in the solution

Field-Induced Dysprosium Single-Molecule Magnet Based on a Redox-Active Fused 1,10-Phenanthroline-Tetrathiafulvalene-1,10-Phenanthroline Bridging Triad

Tetrathiafulvalene and 1,10-phenanthroline moieties present, respectively remarkable redox-active and complexation activities. In this work, we investigated the coordination reaction between the bis(1,10-phenanthro[5,6-b])tetrathiafulvalene triad (L) and the Dy(hfac)3·2H2O metallo precursor. The resulting {[Dy2(hfac)6(L)]·CH2Cl2·C6H14}3 (1) dinuclear complex showed a crystal structure in which the triad L bridged two terminal Dy(hfac)3 units and the supramolecular co-planar arrangement of the triads is driven by donor-acceptor interactions. The frequency dependence of the out-of-phase component of the magnetic susceptibility highlights three distinct maxima under a 2000 Oe static applied magnetic field, a sign that 1 displays a Single-Molecule Magnet (SMM) behavior with multiple magnetic relaxations. Ab initio calculations rationalized the Ising character of the magnetic anisotropy of the DyIII ions and showed that the main anisotropy axes are perpendicular to the co-planar arrangement of the triads. Single-crystal rotating magnetometry confirms the orientation of the main magnetic axis. Finally combining structural analysis and probability of magnetic relaxation pathways through Quantum Tunneling of the Magnetization (QTM) vs. excited states (Orbach), each DyIII center has been attributed to one of the three observed magnetic relaxation times. Such coordination compound can be considered as an ideal candidate to perform redox-magnetic switching

Magnetic and Photo-Physical Properties of Lanthanide Dinuclear Complexes Involving the 4,5-Bis(2-Pyridyl-N-Oxidemethylthio)-4′,5′-Dicarboxylic Acid-Tetrathiafulvalene-, Dimethyl Ester Ligand

The reaction between the 4,5-bis(2-pyridyl-N-oxidemethylthio)-4′,5′-dicarboxylic acid-tetrathiafulvalene-, dimethyl ester ligand (L) and the metallo-precursors Ln(hfac)3·2H2O leads to the formation of two dinuclear complexes of formula [Ln2(hfac)6(L)]·(CH2Cl2)·(C6H14)0.5 (LnIII = DyIII (1) and YbIII (2)). The X-ray structure reveals a quite regular square anti-prism symmetry for the coordination sphere of the lanthanide ion. UV-visible absorption properties have been experimentally measured and rationalized by TD-DFT calculations. The functionalization of the tetrathiafulvalene (TTF) core by two methyl ester moieties induces the appearance of an additional absorption band in the lowest-energy region of the spectrum. The latter has been identified as a HOMO (Highest Occupied Molecular Orbital)→LUMO (Lowest Unoccupied Molecular Orbital) Intra-Ligand Charge Transfer (ILCT) transition in which the HOMO and LUMO are centred on the TTF and methyl ester groups, respectively. Irradiation at 22,222 cm−1 of this ILCT band induces an efficient sensitization of the YbIII-centred emission that can be correlated to the magnetic properties

Total Determination of the Nature of Exchange Interactions in the 3d4f magnetic chain {[Cu(salen)Pr(hfac)3]2(L)}n (L=4.4 -bipyridine, pyrazine)

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Magnétisme et chiralité (des réseaux tridimensionnels à pont oxalate aux chaînes à pont verdazyl)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Lanthanides-TTF complexes displaying single molecule magnet behaviour and luminescence

International audienceLanthanide-based complexes have greatly contributed to the development of mol. magnetism in the last decade and more particularly in the branch of single mol. magnets (SMMs) . The main reasons are their large magnetic moments assocd. to their intrinsic large magnetic anisotropy. The splitting of the multiplet ground state of a single-ion in a given environment is responsible of the trapping of the magnetic moment in one direction in SMMs. However, the analyses of the crystal field effects on the magnetic anisotropy are not so common . A better understanding of the magneto-structural correlations in lanthanide-based complexes should provide tools to improve their potentialities. In this presentation we will focus on the specific magnetic properties of TTF-based lanthanide mononuclear and polynuclear complexes. We will show how optimize the SMM behavior playing on i) the modulation of the supramol. effects via chem. modifications of the TTF ligand , ii) simple mol. engineering modifying the electronic distribution and symmetry of the coordination polyhedron, iii) magnetic dilns. (soln. and doping) and iv) isotopic enrichment of the dysprosium

Hetero-bimetallic Yttrium(lll)-Rhenium(V)(salen) Tetranuclear Complex : Synthesis and Crystal Structure.

WOSInternational audienceSingle crystals of a Y(III)-Re(V)(salen) tetranuclear complex have been obtained by the reaction between the [ReO(salen)(OMe)] and Y(hfac)3 Æ 2H2O compounds (where salen2 is the N,N0-ethan-1,2-diylbis(salicylidenamine) ligand and hfac is the 1,1,1,5,5,5-hexafluo- roacetylacetonate ligand) . This crystallizes in the triclinic, space group P1 (No. 2). The lattice parameters are a = 12.222(5)A ˚ , b = 12.783(5)A ˚ , c = 15.222(4) A ˚ , a = 86.276(5), b = 82.220(5), c = 82.396(5), V = 2332.9(15) A ˚ 3 with Z = 2. The crystallographic structure of the {[Re(salen)]2O3 [Y(hfac)3(H2O)]2}(CHCl3)2(CH2Cl2)2 tetranuclear complex is composed of two terminal Y(hfac)3(H2O) moieties bridged by the linear central {[ReO(salen)]2O} entity