Papers by Jean-Pierre Costes
Synthesis, crystal structure and magnetic properties of dimeric MnIII Schiff base complexes including pseudohalide ligands: Ferromagnetic interactions through phenoxo bridges and single molecule magnetism
Polyhedron, May 1, 2009
ABSTRACT
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Synthesis, Crystal Structure and Magnetic Properties of [Mn((1R , 2R )-Salcy)N3 /NCS] Complexes: Solvent Dependent Crystallization of Monomers, Chains and Dimers
ChemistrySelect, Sep 11, 2017
Five new chiral MnIII complexes [Mn((1R, 2R)‐Salcy)N3]∞⋅CH3CN (1), [Mn((R,R)‐Salcy)N3]∞ (2), [Mn(... more Five new chiral MnIII complexes [Mn((1R, 2R)‐Salcy)N3]∞⋅CH3CN (1), [Mn((R,R)‐Salcy)N3]∞ (2), [Mn((R,R)‐Salcy)N3] (4), [Mn((R,R)‐Salcy)(H2O)N3]⋅C4H8O (5) and [Mn((R,R)‐Salcy)NCS] (6) have been synthesized and characterized by X‐ray structural analysis and magnetic measurements (Salcy=N,N′‐bis(salicylidene)‐1,2‐diaminocyclohexane}. The four azido complexes have been obtained from the previously known [Mn((R,R)‐Salcy)(CH3OH)N3] (3) by crystallization from various solvents. Compounds 1 and 2 are trans‐μ‐1,3‐azide bridged coordination polymers. While 1 forms helical chains, the chain in 2 is formed via translation of a dimeric helicate repeat unit. Compound 3 is a methanol coordinated mononuclear azido complex which forms a 2D‐network through H‐bonding. Compounds 4 and 6 are phenoxo‐bridged dimers without inversion center. Compound 5 is an aqua coordinated mononuclear azido complex, which forms a 1D‐chain through O−H⋅⋅⋅N hydrogen bonding involving axial ligands. In all six compounds MnIII exhibits a characteristic Jahn−Teller elongation. The magnetic coupling in 1 and 2 leads to antiferromagnetic interaction along the chain (2 J=−11.6 cm−1 for 1 and –11.9 cm−1 for 2) through the μ‐1,3‐azide bridge. Compound 3 is weakly antiferromagnetic due to hydrogen bonding interactions in the lattice. The phenoxo dimers (4 and 6) do not have measurable exchange interaction, the low temperature susceptibility being influenced mainly by zero‐field splitting.
Synthesis, Structures, and Magnetic Properties of Novel Mononuclear, Tetranuclear, and 1D Chain Mn<sup>III</sup> Complexes Involving Three Related Asymmetrical Trianionic Ligands
Inorganic Chemistry, Mar 17, 2004
The manganese(III) complexes studied in this report derive from asymmetrical trianionic ligands a... more The manganese(III) complexes studied in this report derive from asymmetrical trianionic ligands abbreviated H(3)L(i) (i = 4-6). These ligands are obtained through reaction of salicylaldehyde with &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;half-units&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;, the latter resulting from monocondensation of different diamines with phenylsalicylate,. Upon deprotonation, L(i) (i = 4-6) possess an inner N(2)O(2) coordination site with one amido, one imine, and two phenoxo functions, and an outer amido oxygen donor. The trianionic character of such ligands yields original neutral complexes with the L/Mn stoichiometry. The crystal and molecular structures of three complexes have been determined at 190 K (1) or 180 K (2 and 3). Complex 1 crystallizes in the triclinic space group P (No. 2): a = 7.8582(14) A, b = 10.9225(16) A, c = 12.4882(18) A, alpha = 67.231(14) degrees, beta = 72.134(14) degrees, gamma = 82.589(13) degrees, V = 940.6(3) A(3), Z = 2. Complex 2 crystallizes in the orthorhombic space group Pbcn (Nuomicron. 60): a = 23.8283(15) A, b = 11.1605(7) A, c = 26.152(2) A, V = 6954.8(8) A(3), Z = 8, while complex 3 crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 11.7443(14) A, b = 7.5996(10) A, c = 18.029(2) A, beta = 100.604(10) degrees, V = 1581.6(3) A(3), Z = 4. Owing to hydrogen bonds and pi-pi stackings, the mononuclear neutral molecules of 1 are arranged in a 2D network while complexes 2 and 3 are tetranuclear and polymeric (1D chain) species, respectively, owing to the bridging ability of the oxygen atom of the amido function. The experimental magnetic susceptibilities of complexes 2 and 3 indicate the occurrence of similarly weak Mn(III)-Mn(III) antiferromagnetic interactions (J = -1.1 cm(-1)). Single ion zero-field splitting of manganese(III) must be taken into account for satisfactorily fitting the data by exact calculation of the energy levels associated to the spin Hamiltonian through diagonalization of the full matrix for axial symmetry in 2 (J = - 1.1 cm(-1), D(1) = 2.2 cm(-1), D(2) = -2.8 cm(-1)), D(1) and D(2) being associated to the six- and five-coordinate Mn ions, respectively. A weaker antiferromagnetic interaction (J = - 0.2 cm(-1)) operates through pi-pi stacking in complex 1. Complex 3 is a weak ferromagnet (ordering temperature approximately 7 K) as a result of the spin canting originating from the crystal packing.
Polyhedron, 2019
Use of 155 Gd Mössbauer spectroscopy allows a straightforward characterization of heterodinuclear... more Use of 155 Gd Mössbauer spectroscopy allows a straightforward characterization of heterodinuclear Ln-Ln' complexes (LLnLn'(NO3)3•(H2O)2) with a tripodal ligand L, possessing two different N4O3 and O3O3 coordination sites. Thanks to the isomer shift value, the location of the Gd III ion is confirmed; the Gd atom in the Gd-Ln' series (Ln' = Ce, Nd, Eu) occupies the inner N4O3 site with a eight-coordination (N4O3 + O), but on the other hand the Gd atom in the Ln-Gd series (Ln = Dy, Er, Yb) resides in the outer O3O3 site with a ten-coordination (O3O3 + O2 +O2). The smaller isomer shift values for the former indicate that coordination of the basic nitrogen atoms enhances the 6s orbital population. With the help of 151 Eu Mössbauer spectroscopy, we demonstrate that the Gd-Eu entity is a genuine heterodinuclear complex, in which the Gd III ion is located in the inner site and the Eu III ion in the outer oxygenated site. This result highlights the feasibility of our synthetic process described earlier to introduce in a heterodinuclear complex two consecutive ions of the periodic table. And the slow paramagnetic relaxation observed in the 166 Er Mössbauer spectrum of the Er-Gd complex confirms presence of a magnetic interaction in the genuine Er-Gd complex.
Journal de Chimie Physique, 1976
SOMMAIRE L'étude des spectres de résonance nucléaire ('H, n B et 10F) de différents mélanges Me3N... more SOMMAIRE L'étude des spectres de résonance nucléaire ('H, n B et 10F) de différents mélanges Me3N.BZ3/BT3 (Z = C3H, ou CjHj et T = Cl, F et OCH3) a permis de mettre en évidence l'existence d'équilibres de redistribution entre les différentes espèces libres BZnT3_", et complexées Me3N.BZnT3_". Une comparaison avec le comportement des systèmes analogues mais dépourvus d'amine (BZ3/BT3) montre que l'influence de cette dernière varie suivant la nature des substituants Z et T. SUMMARY 1H, llB and 10F magnetic resonance studies of redistribution in the systems Me3N.BZ3/BT3 (Z = C3H, or C.,H0 and T = Cl, F and OCIl3) show that equilibria between free (BZnT.i-") and complexed (Mc3N.BZ"T3_n) species occur. From a comparison with uncomplexed systems (BZ3/BT3), the amine influence appears to be connected to the nature of T and Z substituents.
ChemInform Abstract: UMVERTEILUNG DER MONOFUNKTIONELLEN METHYLMERCAPTO‐ UND DIMETHYLAMINOGRUPPEN AN TRIKOORDINIERTEN BORATOMEN
Chemischer Informationsdienst, 1975
Hydrothermal investigation of the lanthanide (Ln=La, Ce, Pr, Nd, Sm) 2,6-pyridinedicarboxylate system
Inorganica Chimica Acta, 2002
In this paper, two new dipicolinate complexes, Ln2(dipic)3(H2O)3 (1) with Ln=La, Ce, Pr, Nd, Sm a... more In this paper, two new dipicolinate complexes, Ln2(dipic)3(H2O)3 (1) with Ln=La, Ce, Pr, Nd, Sm and Ce3(dipic)5(H2O)2 (2), are described. Hydrothermal synthesis, crystal structure and thermal behaviour of both compounds are described, as well as the magnetic behaviour of the trinuclear complex (2). The structures consist of LaO7N2, LaO7N (1) and CeO7N, CeO6N3 (2) polyhedra linked to form three-dimensional networks.
Crystal Structures and Magnetic Properties of Nickel Complexes with Hydrotris(pyrazolyl)borate Ligand and Double Bridged by Phosphate Esters
Inorganic Chemistry, 2011
The reaction between [NiTp*(μ-OH)]2 (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate) and (RO)2P(O)O... more The reaction between [NiTp*(μ-OH)]2 (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate) and (RO)2P(O)OH (R = Et, Bu, 4-NO2-Ph) affords the dinuclear nickel phosphates [NiTp*(μ-O2P(OR)2)]2 (R = Et (1), Bu (2), 4-NO2-Ph (3)), which have been studied by spectroscopic methods (IR, UV-vis, and (1)H NMR). In chloroform solution, those complexes exhibit isotropically shifted (1)H NMR resonances. Their molecular structures reveal that they all have an eight-membered Ni2O4P2 ring which possesses two nickel centers bridged to each other by two isobidentate phosphate ligands. Magnetic studies on 1-3 and other similar complexes (4 and 5) reveal antiferromagnetic behavior at low temperatures as well as an interesting correlation between calculated D values and the planarity of eight-membered Ni2O4P2 rings.
Contribution of 155Gd Mössbauer data to the study of the magnetic interaction in heterodinuclear 3d–Gd (3d = Cu, Ni) coordination complexes
Dalton Transactions, 2019
The observed 155Gd Mössbauer isomer shifts of 3d–Gd complexes give an experimental proof for the ... more The observed 155Gd Mössbauer isomer shifts of 3d–Gd complexes give an experimental proof for the participation of 5d Gd orbitals to the magnetic interaction in these 3d–Gd complexes.
Bis-dinuclear (Cu–Gd)<sub>2</sub>complexes with a probable helicate structure
Dalton Transactions, 2004
Two ligands have been designed to simultaneously favour complexation of 3d and 4f metal ions and ... more Two ligands have been designed to simultaneously favour complexation of 3d and 4f metal ions and the formation of helical structures. This synthetic strategy has allowed the isolation of two bis-dinuclear (Cu-Gd)(2) complexes [L(i)(2)Cu(2)Gd(2)(NO(3))(6)] derived from 3-alkoxysalicylaldehyde and 4,4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-diaminodiphenylmethane. The magnetic data shows that both bis-dinuclear complexes behave as two practically independent (Cu-Gd) pairs, each presenting a ferromagnetic interaction (J= 4.6 cm(-1)). Very weak additional antiferromagnetic interactions, probably originating from intra- and/or intermolecular [small pi] stackings, are suggested by the decrease in chiMT below 8 K.
Polyhedron, Sep 1, 2012
Two heterometallic complexes [{Cu(phen) 2 } 2 {Cr 2 (l-OH) 2 (nta) 2 }][Cr 2 (l-OH) 2 (nta) 2 ]Á8... more Two heterometallic complexes [{Cu(phen) 2 } 2 {Cr 2 (l-OH) 2 (nta) 2 }][Cr 2 (l-OH) 2 (nta) 2 ]Á8H 2 O (I) and [{Cu(phen) , where nta is the nitrilotriacetate ligand and dmf is dimethylfomamide, phen is o,o 0 -phenanthroline, have been prepared and structurally characterized by single-crystal X-ray crystallography. Both compounds display an ionic type structure, with close geometric parameters, containing {Cr 2 (l-OH) 2 (nta) 2 } and {Ga 2 (l-OH) 2 (nta) 2 } entyties for I and III, respectively. These dimeric di-l-hydroxy units exhibit different coordination functions. In the tetranuclear Cu 2 Cr 2 and Cu 2 Ga 2 complex cations they are involved in a bidentate bridging form being linked to the cooper atoms through two symmetrically related oxygen atoms of the carboxylate groups. The anionic forms [Cr 2 (l-OH) 2 (nta) 2 ] 2À and [Ga 2 (l-OH) 2 (nta) 2 ] 2À are non-coordinating and only involved in a multiple hydrogen bonds architecture. Comparative analysis of the temperature dependence of EPR spectrum and magnetic susceptibility of compound I and III, showed that the magnetic properties of tetranuclear cluster [{Cu(phen)} 2 Cr 2 (OH) 2 (nta) 2 ] are dominated by strong antiferromagnetic interaction between chromium ions (J iso CrCr = À13.4 cm À1 ). The interaction between chromium(III) and copper(II) ions via syn-anti carboxylic groups has a small antiferromagnetic values (J iso CrCu = À0.23 cm À1 ). The small anisotropy of the exchange interaction between chromium ions manifests itself only in the EPR spectra.
Syntheses, Structures, and Magnetic Properties of Symmetric and Dissymmetric Ester‐Functionalized 3d‐4f Schiff Base Complexes
European Journal of Inorganic Chemistry, Jan 5, 2018
Ester-functionalized bi-compartmental Schiff-base ligand and their 3d-Ln complexes with 3d = Ni(I... more Ester-functionalized bi-compartmental Schiff-base ligand and their 3d-Ln complexes with 3d = Ni(II), Cu(II) or Zn(II) and Ln = Gd(III), Tb(III) or Dy(III) are reported. The modularity of the Schiff-base structure (i.e. symmetric vs dissymmetric, ester-group) is illustrated to highlight the possibility offered by the ester for facile functionalization at the periphery of the ligand, in addition of its electron-withdrawing effect on the complexing core. The introduction of a chiral pool (i.e. a menthyl group) at the ester functions led to a transfer of chirality to the coordination sphere of the Ln in the solid state. Several 3d-4f complexes have been found to crystallize as NO3- or OH- bridged compounds. Crystal structures and magnetic behaviors are reported for all the 3d-4f complexes.
Structural and Magnetic Studies of New Ni <sup>II</sup> –Ln <sup>III</sup> Complexes
European Journal of Inorganic Chemistry, Jun 1, 2010
The synthesis, structure determination and magnetic studies of dinuclear NiII–LnIII complexes (Ln... more The synthesis, structure determination and magnetic studies of dinuclear NiII–LnIII complexes (Ln = Y, La, Pr, Gd) involving ortho‐vanillin as the main ligand are described. Structural studies demonstrate that two types of complexes can be obtained with hexacoordinate Ni ions in slightly deformed octahedral environments and nine‐ or ten‐coordinate lanthanide ions. The Ni and Gd ions are linked by two phenoxo bridges in one complex and two phenoxo bridges and one nitrato bridge in the other. A ferromagnetic interaction operates in the Ni–Gd complex, with a D zero field splitting term for the nickel ion, as in the Ni–La and Ni–Y complexes where these D terms are the only active magnetic terms. Among the factors responsible for the different structures are ionic radii of the Ln ions, solvent and configuration change of the starting nickel complex; the role of solvent seems to be preponderant. The weak value of the ferromagnetic Ni–Gd interaction can be explained by the flexibility and the departure from planarity of the two independent ortho‐vanillin ligands.
Inorganic Chemistry, Feb 3, 2006
Based on self-assembly of the dissymmetrical mononuclear entity CuL( with Mn(II), two trinuclear ... more Based on self-assembly of the dissymmetrical mononuclear entity CuL( with Mn(II), two trinuclear complexes were prepared. They are of the formula [(LCuN 3 ) 2 Mn(CH 3 OH) 2 ] AE 2CH 3 OH AE 2H 2 O (1) and [(LCuSCN) 2 Mn(H 2 O) 2 ] AE 4CH 3 OH (2). Their magnetic properties were studied by susceptibility versus temperature measurement, the best fitting of the experimental data led to J = À14.40 cm À1 for 1 and J = À15.48 cm À1 for 2. Hydrogen bonds help complex 1 to produce a novel S type one-dimensional chain-like supramolecular structure. In complex 2, ClÁ Á ÁCl interaction also results in the formation of a one-dimensional structure.
Synthesis, Structure, and Magnetic Properties of Heterometallic Dicyanamide-Bridged Cu−Na and Cu−Gd One-Dimensional Polymers
Inorganic Chemistry, Oct 23, 2004
The monometallic precursors L1Cu and L2Cu (L1H2 standing for 1,3-bis((3-ethoxysalicylidene)amino)... more The monometallic precursors L1Cu and L2Cu (L1H2 standing for 1,3-bis((3-ethoxysalicylidene)amino) propane and L2H2 standing for 1,2-bis((3-methoxysalicylidene)amino) ethane) react with sodium dicyanamide (dca) (NaN3C2), a mixture of gadolinium nitrate, and sodium dicyanamide to yield heterodinuclear L2CuNa(NCNCN) and L1CuGd(NO3)(NCNCN)2 entities. The structural determination shows that two Cu-Na entities are linked by dca with an original mu1,1 coordination mode, evidenced here for the first time, to yield tetranuclear complexes. Two hydrogen bonds operate between the water molecule coordinated to one of the sodium ions and the free nitrogen atoms of two dca ligands, yielding infinite zigzag chains. The structural determination of the Cu-Gd entities indicates that they are held together by two dca ligands, bridging alternately Cu to Gd and Gd to Gd cations, in the more common mu1,5 mode to yield a one-dimensional (1D) network. The dca ligands are not able to transmit interaction between the magnetically active centers in these chains, which are the unique example of structurally characterized Cu-Gd complexes involving dca ligands.
Cu-Ln complexes involving non-symmetrical ligands able to introduce asymmetric centres in the vicinity of Ln ions
Polyhedron
Chemistry Journal of Moldova, 2006
The magnetic susceptibility (χT) of an unusual dissymmetric binuclear manganese corboxylate compl... more The magnetic susceptibility (χT) of an unusual dissymmetric binuclear manganese corboxylate complex has been measured from 2 to 300K. The magnetic data which have been fitted with help of the Heisenberg Dirac Van Vleck HDVV spin-exchange Hamiltonian H = − J S 1 S 2 , indicate that an antiferromagnetic interaction equal to J = -0.90(1) cm-1 is present. A correlation between J values and Mn-H2O-Mn angles has been tempted.
European Journal of Inorganic Chemistry, 2020
Trianionic ligands with an inner N2O2, an outer O2O2 or O2O coordination site and an oxygen atom ... more Trianionic ligands with an inner N2O2, an outer O2O2 or O2O coordination site and an oxygen atom coming from an amide function not involved in these sites yield dinuclear Cu‐Ln complexes that self‐assemble into tetranuclear species with an alternate arrangement of Cu and Ln ions. This alternate Cu‐Gd arrangement impedes Cu–Cu and Gd‐Gd interactions that could be antiferromagnetic and favours ferromagnetic Cu‐Gd interactions whose strength depends on the nature of the bridge, the phenoxo bridge made of a single oxygen atom or the amidato bridge made of three NCO atoms. Depending on the ligands, the phenoxo bridges can be single (CuOGd) or double (CuO2Gd), while the amidato bridge is always a single (CuNCOGd) bridge. A particular complex involving a trinuclear Cu‐Gd‐Cu arrangement through two amidato bridges confirms that the Cu‐Gd interaction through the amidato bridge is always weaker than the interaction through the phenoxo bridge. It has been possible to obtain complexes with an a...
Polyhedron, 2018
Reaction of diethylenetriamine with phenol derivatives possessing a phenyl ester function yields ... more Reaction of diethylenetriamine with phenol derivatives possessing a phenyl ester function yields a ligand corresponding to the monocondensation of diethylenetriamine with the phenol derivative. In a following step, its coordination to copper ions gives a neutral complex that is able to react with orthovanillin in order to yield an original complex made of a non symmetric ligand possessing three nitrogen, amide, imine and secondary amine, and four oxygen, amide, phenol (2) and methoxy donor atoms, thanks to the kinetic template effect. In our example, the copper center brings the three reactive functions (first primary amine and aldehyde, then amide) in close vicinity so that the formation of an imine function and the protonation of the amide function can occur. The structural determination of the resulting complex confirms an unexpected copper coordination.
Dalton Transactions, 2019
Solvents and ancillary ligands play a major role in the formation of genuine heterotrinuclear Ni–... more Solvents and ancillary ligands play a major role in the formation of genuine heterotrinuclear Ni–Ln–M complexes. Ab initio calculations give further insights into the anisotropy of these systems.
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Papers by Jean-Pierre Costes