Miguel Julve

University of Valencia, Valenza, Valencia, Spain

Are you Miguel Julve?

Claim your profile

Publications (535)2281.81 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We report on a novel manganese(III)-porphyrin complex with the formula [Mn(III) (TPP)(3,5-Me2 pyNO)2 ]ClO4 ⋅CH3 CN (2; 3,5-Me2 pyNO=3,5-dimethylpyridine N-oxide, H2 TPP=5,10,15,20-tetraphenylporphyrin), in which the Mn(III) ion is six-coordinate with two monodentate 3,5-Me2 pyNO molecules and a tetradentate TPP ligand to build a tetragonally elongated octahedral geometry. The environment in 2 is responsible for the large and negative axial zero-field splitting (D=-3.8 cm(-1) ), low rhombicity (E/|D|=0.04) of the high-spin Mn(III) ion, and, ultimately, for the observation of slow magnetic-relaxation effects (Ea =15.5 cm(-1) at H=1000 G) in this rare example of a manganese-based single-ion magnet (SIM). Structural, magnetic, and electronic characterizations were carried out by means of single-crystal diffraction studies, variable-temperature direct- and alternating-current measurements and high-frequency and -field EPR spectroscopic analysis followed by quantum-chemical calculations. Slow magnetic-relaxation effects were also observed in the already known analogous compound [Mn(III) (TPP)Cl] (1; Ea =10.5 cm(-1) at H=1000 G). The results obtained for 1 and 2 are compared and discussed herein.
    Chemistry - A European Journal 10/2015; DOI:10.1002/chem.201502637 · 5.73 Impact Factor
  • José Martínez-Lillo · Miguel Julve · Euan K. Brechin ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Two novel FeII–ReIV compounds of general formula [FeII(DEA)6][ReIVX6] where DEA = diethylacetamide and X = Cl (1) and Br (2) have been prepared and magnetostructurally characterised. Complexes 1 and 2 are isomorphic ionic salts that crystallise in the trigonal crystal system with space group R(−3). The rhenium(IV) ion in 1 and 2 is six-coordinate with six chloro (1) or bromo (2) ligands building a regular octahedral chromophore. The FeII ion is also six-coordinate, and bonded to six oxygen atoms from six DEA molecules. [FeII(DEA)6]2+ cations and [ReIVX6]2− anions alternate in the crystal lattice of 1 and 2 generating supramolecular structures whose magnetic properties are dominated by the high anisotropy of the six-coordinate iron(II) and rhenium(IV) ions. Variable-temperature magnetic susceptibility data of 1 and 2 are well reproduced by a model of isolated S = 2 (FeII) and S = 3/2 (ReIV) centres with high values of the local zero-field splitting. 1 and 2 are the first examples of hexahalorhenate(IV) salts incorporating FeII complex cations to have been magnetostructurally investigated.
    Polyhedron 09/2015; 98. DOI:10.1016/j.poly.2015.05.036 · 2.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Five bis(oxamato)palladate(II) complexes of the formulae (n-Bu4N)2[Pd(4-Fpma)2] (1), (n-Bu4N)2[Pd(4-Clpma)2] (2), (n-Bu4N)2[Pd(4-Brpma)2] (3), (n-Bu4N)2[Pd(4-Brpma)2]·H2O (3a), (n-Bu4N)2[Pd(4-MeOpma)2] (4) and (n-Bu4N)2[Pd(4-Isopma)2] (5) (n-Bu4N+ = tetra-n-butylammonium, 4-Fpma = N-4-fluorophenyloxamate, 4-Clpma = N-4-chlorophenyloxamate, 4-Brpma = N-4-bromophenyloxamate, 4-MeOpma = N-4-methoxyphenyloxamate and 4-isopma = N-4-isopropylphenyloxamate) have been easily prepared and characterized by spectroscopic methods and the crystal structures of two of them (3a and 4) have been determined by single crystal X-ray diffraction. Each palladium(II) ion in 3a and 4 is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated oxamate ligands building a centrosymmetric square planar PdN2O2 surrounding. The values of the Pd–N and Pd–O bond lengths vary in the ranges 2.034(3)–2.043(4) and 1.999(4)–2.013(3) Å, respectively. The reduced bite of the chelating oxamate ligands [81.3(2)–81.7(1) (3a) and 81.61(7)° (4)] is at the origin of the mean distortion of the ideal square environment. The catalytic role of compounds 1–5 as structurally well-defined precatalysts for the Heck-vinylation of a series of aryl iodide/bromide derivatives in n-Bu4NBr as a benign nonaqueous ionic liquid (i.d. molten salt) has been examined and compared with some commercially available palladium(II/0) complexes. From this study, it appears that the oxamate-containing precatalysts 1–5 are not just ecologically benign, but also highly efficient, easily recoverable and reusable at least eight times without any relevant loss of catalytic activity or leaching from the ionic liquid medium.
    09/2015; DOI:10.1039/C5QI00093A
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two new Re(iv) compounds of formulae H2tppz[ReCl6] () and [Cu(bpzm)2(μ-Cl)ReCl3(μ-ox)Cu(bpzm)2(μ-ox)ReCl3(μ-Cl)]n () [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and bpzm = bis(pyrazolyl-1-yl)methane] have been prepared and their crystal structures determined by X-ray diffraction on single crystals. Compound is a mononuclear species whose structure consists of octahedral hexachlororhenate(iv) anions and diprotonated H2tppz(2+) cations which are arranged in the unit cell as alternating anionic and cationic layers, held together by electrostatic forces. The structure of is made up of alternating [Cu(1)(bpzm)2](2+) and [(ox)ReCl3(μ-Cl)Cu(2)(bpzm)2(μ-Cl)ReCl3(ox)](2-) entities interlinked by oxalate bridges to afford a neutral heterobimetallic chain. The oxalate group adopts the didentate (at Re)/monodentate (at Cu) bridging mode. The magnetic behavior of and has been investigated over the temperature range 1.9-295 K. is a magnetically diluted Re(iv) complex, the relatively large value of the zero-field splitting of the ground level [D = -15.8(2) cm(-1)] accounting for the variation of χMT in the low temperature range. Weak intrachain ferromagnetic interactions between Re(iv) and Cu(ii) through oxalate (J1 = +0.15 cm(-1)) and single chloro (J2 = +4.9 cm(-1)) bridges occur in which are obscured by the large zero-field splitting of the Re(iv) ion (DRe = 42 cm(-1)). In addition, interchain antiferromagnetic interactions are also involved in which are responsible for the metamagnetic behavior observed, the value of the critical dc magnetic field (Hc) being 20 kOe.
    Dalton Transactions 08/2015; 44(39). DOI:10.1039/c5dt02522b · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Three isostructural compounds of the formula {[M(bipy)(H2O)(H2P2O7)]2·2H2O} [bipy = 2,2'-bipyridine; M = Ni (1), Co (2), Mn (3)] have been isolated from aqueous solutions containing the corresponding metal(II) chloride hydrate with a bipy and sodium pyrophosphate solution in a 1:1:2 molar ratio, and their structures were determined by single-crystal X-ray diffraction. The structures of 1-3 consist of neutral aqua(2,2'-bipyridine)metal(II) dinuclear units bridged by two dihydrogenpyrophosphate groups adopting a bidentate/monodentate mode. Each metal ion in 1-3 is six-coordinate in a distorted octahedral geometry, with the reduced value of the angle subtended by the chelating bipy at the metal ion [79.6(1)° (1), 77.32(7)° (2), and 72.9(1)° (3)] being the main source of this distortion. The values of the intramolecular metal-metal separation are 5.271(1) Å (1), 5.3065(8) Å (2), and 5.371(1) Å (3). Magnetic susceptibility measurements on polycrystalline samples of 1-3 in the temperature range 1.9-300 K shows weak intramolecular ferromagnetic [J = +1.86(2) cm(-1) (1) and +0.25(1) cm(-1) (2)] and antiferromagnetic [J = -0.48(1) cm(-1) (3)] coupling, with the spin Hamiltonian being defined as H = -JSM1·SM1a. This rarely observed coordination mode for dihydrogenpyrophosphate leads to ferromagnetic coupling in complexes of nickel(II) or cobalt(II).
    Inorganic Chemistry 06/2015; 54(13). DOI:10.1021/acs.inorgchem.5b00866 · 4.76 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A relatively large antiferromagnetic interaction between the two chromium(III) ions from the molecular square [{Cr(dmso)3}2{Nb(Cr-O)2(C2O4)2}2] (1) (J = -12.0 cm-1) is mediated by the diamagnetic oxo-Nb(V)-oxo pathway, its nature and magnitude being substantiated by DFT type theoretical calculations
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The work presented in this review constitutes a successful extension of our group's research on the chemistry and physics of dinuclear copper(II) metallacyclophanes with aromatic polyoxalamide ligands. The design and synthesis of metallacyclic complexes that contain multiple electro- and photoactive (either metal- or ligand-based) spin carriers and the study of their spectroscopic and magnetic properties as well as their redox and photochemical activity are of large interest in the multidisciplinary field of metallosupramolecular chemistry. In doing this, a ligand design approach has been followed which is based on the copper(II)-mediated self-assembly of bis(oxamato) bridging ligands possessing potentially electro- and photoactive, extended π-conjugated aromatic spacers. This strategy benefits from the inherent physical and chemical properties of aromatic organic molecules by functionalizing them with two oxamato donor groups to get dinucleating ligands that are then able to self-assemble with square planar CuII ions affording the targeted oxamato-based dicopper(II) metallacyclophanes. The organic functionalization in this new class of metallacyclic systems constitutes a unique example of ligand design for the supramolecular control of the structure and magnetic properties, as well as the electro- and photochemical activities. This novel class of oxamato-based dicopper(II) metallacyclophanes provides excellent models for the fundamental study on through-ligand long-distance and redox- or photo-triggered electron exchange phenomena, which are two central topics in molecular magnetism and molecular electronics. Using these simple dinuclear metallacyclic complexes as dynamic chemical systems to perform specific and selective tasks under the control of an external (electro- and/or photochemical) stimulus that switches “ON” and “OFF” their electronic (optical and/or magnetic) properties may have an enormous impact in several domains of molecular nanoscience. Hence, oxamato-based dicopper(II) metallacyclophanes appear as very promising candidates to get multifunctional magnetic devices controlling and facilitating the spin communication (“molecular magnetic couplers” and “molecular magnetic wires”) or exhibiting charge storage (“molecular magnetic capacitors”) and bistable spin behavior (“molecular magnetic rectifiers” and “molecular magnetic switches”) for potential applications in information processing and storage in the emerging areas of molecular spintronics and quantum computing. Moreover, because of the potential high affinity for a variety of metal surfaces through the free carbonyl-oxygen atoms of the oxamate groups, they are very appealing candidates for the study of coherent electron transport through single molecules.
    Coordination Chemistry Reviews 06/2015; 303. DOI:10.1016/j.ccr.2015.05.013 · 12.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The novel Re(II) complex NBu4[Re(NO)Br4(Hnic)] (1) and the heterodinuclear compounds [Re(NO)Br4(µ-nic)Ni(dmphen)2]•½CH3CN (2), [Re(NO)Br4(µ-nic)Co(dmphen)2]•½MeOH (3), [Re(NO)Br4(µ-nic)Mn(dmphen)(H2O)2]•dmphen (4), [Re(NO)Br4(µ-nic)Cu(bipy)2] (5) [Re(NO)Br4(µ-nic)Cu(dmphen)2] (5’) (NBu4+ = tetra-n-butylammonium cation, Hnic = 3-pyridinecarboxylic acid, dmphen = 2,9-dimethyl-1,10-phenanthroline, bipy = 2,2’-bipyridine) have been prepared and the structures of 1-5 determined by single crystal X-ray diffraction. The structure of 1 consists of [Re(NO)Br4(Hnic)]- anions and NBu4+ cations. Each Re(II) is six-coordinate with four bromide ligands, a linear nitrosyl group and a nitrogen atom from the Hnic molecule, in a distorted octahedral surrounding. The structures of 2-5 are made up of discrete heterodinuclear Re(II)M(II) units where the fully deprotonated [Re(NO)Br4(nic)]2- entity acts as a didentate ligand through the carboxylate group towards the [Ni(dmphen)2]2+ (2), [Co(dmphen)2]2+ (3), [Mn(dmphen)(H2O)2]2+ (4) and [Cu(bipy)2]2+ (5) fragments, the Re-M separation across the nic bridge being 7.8736(8) (2), 7.9632(10) (3), 7.7600(6) (4) and 8.2148(7) Å (5). The environment of the Re(II) ion in 2-5 is the same as in 1 and all M(II) are six-coordinate in highly distorted octahedral surroundings, the main source of the distortion being due to the reduced bite of the chelating carboxylate. The magnetic properties of 1-5’ were investigated in the temperature range 1,9-300 K. 1 behaves as a quasi magnetically isolated spin doublet with very weak antiferromagnetic interactions through space Br…Br contacts. Its magnetic susceptibility data were successfully modeled through a deep analysis of the influence of the ligand field, spin-orbit coupling, tetragonal distortion and covalence effects as variable parameters. Compounds 2-5’ exhibit weak antiferromagnetic interactions. The intramolecular exchange pathway in this family being discarded because of the symmetry of magnetic orbital of the Re(II) ion (dxy) precludes any spin delocalization on the bridging nic orbitals, the observed magnetic interactions are most likely mediated by - type interactions between the peripheral ligands which occur in them. Only in the case of 4, short through space Br…Br contacts of ca. 4.03 Å (values larger than 5.5 Å in 2, 3 and 5) could be involved in the exchange coupling.
    Dalton Transactions 05/2015; 44(25). DOI:10.1039/C5DT01321F · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two novel ReIV compounds of formula (Hbpym)2[ReIVBr6]·4H2O (1) and (H4biim)[ReIVBr6]·4H2O (2) [Hbpym+ = 2,2′-bipyrimidinium cation and H4biim2+ = 2,2′-biimidazolium dication] have been prepared and magnetostructurally characterized. 1 and 2 exhibit distinct crystal packing, and the presence of weak intermolecular contacts, such as Re-Br···Br-Re (1 and 2), Re-Br···(H2O)···Br-Re (1 and 2), and Re-Br···π···Br-Re (2), lead to different magnetic behaviors. While 1 is antiferromagnetic, 2 is a ferromagnetic compound and indeed the first example of ferromagnetic salt based on the hexabromorhenate(IV) anion. These results suggest a straightforward synthetic route to the preparation of new ferromagnetically coupled ReIV compounds.
    Crystal Growth & Design 05/2015; 15(6):150512140538001. DOI:10.1021/acs.cgd.5b00436 · 4.89 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The synthesis, crystal structure and preliminary magnetic characterization of a new heterobimetallic [MnII5CuII5] wheel containing a flexible bis-oxamate type ligand are described. This decanuclear compound exhibits a relatively strong intra-wheel antiferromagnetic interaction leading to a ground spin state S = 10.
    Dalton Transactions 05/2015; 44(24). DOI:10.1039/C5DT00996K · 4.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The synthesis, crystal structure and preliminary magnetic characterization of a new heterobimetallic [MnII5CuII5] wheel containing a flexible bis-oxamate type ligand are described. This decanuclear compound exhibits a relatively strong intra-wheel antiferromagnetic interaction leading to a ground spin state S = 10.
    Dalton Transactions 05/2015; · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new heteroleptic 1D Cu(I)-Re(IV) coordination polymer of the formula {Cu(I)Re(IV)Cl4(μ-Cl)(μ-pyz)[Re(IV)Cl4(μ-bpym)]}n·nMeNO2 (1; pyz = pyrazine, bpym = 2,2'-bipyrimidine) has been prepared through the Cu(I)-mediated self-assembly of two different Re(IV) metalloligands, namely, [ReCl5(pyz)](-) and [ReCl4(bpym)]. 1 consists of chiral branched chains with an overall rack-type architecture displaying photoemission and magnetic ordering. These results constitute a first step toward making new multifunctional magnetic materials based on mixed 3d-5d molecular systems.
    Inorganic Chemistry 05/2015; 54(10). DOI:10.1021/acs.inorgchem.5b00502 · 4.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The preparation, spectroscopic characterization and X-ray crystal structure of two novel one-dimensional compounds of formula [MII(tppz)(NCS)(μ-1,3-NCS)]n [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and M = Co(1) and Ni (2)] are reported. 1 and 2 are isomorphous compounds and they crystallize in the P21/n space group. Their structures are made up of zig-zag chains of cobalt(II) (1) and nickel(II) ions (2) bridged by single end-to-end thiocyanate groups with a tridentate tppz molecule and a terminally bound thiocyanate-N ligand achieving distorted MN5S octahedral surroundings around each metal center. The main source of the distortion of the ideal octahedron is due to the geometrical constraints issued from the occurrence of two fused five-member chelate rings of the tridentate tppz ligand, the values of the N-M-N bond angles covering the range 75.58(9)-78.66(9)º. The M-N bond lengths vary in the range 2.025(3)-2.116(29 (1) and 2.001(2)-2.079(2) Å (2) and they are shorter than the M-S bond distance [2.6395(10) (1) and 2.5225(9) Å (2)]. The values of the intrachain metal-metal separation are 6.4197(7) (1) and 6.3257(5) Å (2). The magnetic properties of 1 and 2 have been investigated in the temperature range 1.9-300 K. Both compounds exhibit intrachain ferromagnetic interactions with values of the magnetic coupling (J) of +4.60 (1) and +7.82 cm-1 (2) [the spin Hamiltonian being defined as H ̂=- J∑_(i=1)^(n-1)▒〖S ̂_i S ̂_(i+1) 〗].
    Crystal Growth & Design 05/2015; 15(5):2380-2388. DOI:10.1021/acs.cgd.5b00176 · 4.89 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two new two-dimensional homometallic compounds {[M2(bpm)(ox)2]n·5nH2O} with M = Co(II) (1) and Zn(II) (2) and the mononuclear nickel(II) complex [Ni(bpm)2(ox)]·2H2O (3) [bpm = 2,2’-bipyrimidine and ox = oxalate] have been prepared and structurally characterized. 1 and 2 are isostructural compounds whose structures are made up of oxalate-bridged M(II) cations cross-linked by bis-bidentate bpm molecules to afford a honeycomb layered network extending in the crystallographic ab plane. The layers are eclipsed along the crystallographic c axis and show graphitic-like interactions between the bpm rings. The three- dimensional supramolecular network deriving from such interactions is characterized by hexagonal- shaped channels extending in the same direction. Each M(II) ion in 1 and 2 is tris-chelated with four oxygen atoms from two oxalate groups and two bpm-nitrogen atoms building a distorted octahedral sur- rounding. The reduced values of the angles subtended by the bis-chelating bpm [77.69(8) (1) and 25 76.59(8)° (2)] and oxalate [79.69(6) (1) and 80.01(5)° (2)] are the main factors accounting for this distortion. The values of the metal–metal separation through bridging bpm are 5.6956(7) (1) and 5.7572(9) Å (2), whereas those across the bis-bidentate oxalate are 5.4306(4) (1) and 5.4058(5) Å (2). 3 is a neutral mono- nuclear nickel(II) complex where each metal ion is six-coordinate with four nitrogen atoms from two bpm ligands in a cis arrangement and two oxalate-oxygen atoms building a somewhat distorted octahedral surrounding. The values of the angles subtended at the nickel(II) ion by bpm and oxalate are 78.14(4) and 80.95(5)°, respectively. The magnetic properties of 1 have been investigated in the temperature range 1.9–295 K. They are typical of an overall antiferromagnetic coupling with a maximum of the magnetic susceptibility at 22.0 K. The analysis of the susceptibility data of 1 through an effective spin Hamiltonian 35 allowed a satisfactory simulation in the temperature range 10–295 K with the best-fit parameters λ = -110 cm−1, α = 1.1, |Δ| = 400 cm−1, Jox = −11.1 cm−1 and Jbpm = −5.0 cm−1. The values of the antifer coupling through bpm and ox in 1 have also been supported by electronic structure calculations based on Density Functional Theory (DFT) and they compare well with those reported in the literature for bpm-bridged dicobalt(II) complexes and oxalate-bridged cobalt(II) chains.
    Dalton Transactions 05/2015; 44(24). DOI:10.1039/c5dt00553a · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of the mononuclear rhenium(IV) precursor [ReBr5 (H2 pydc)](-) (H2 pydc=3,5-pyridinedicarboxylic acid) as a metalloligand towards dysprosium(III) afforded the first heterobimetallic Re(IV) -Dy(III) complex. Crystal structures and static and dynamic magnetic properties of both rhenium-containing species are reported herein. The 5d-4f compound shows an extended 1D structure and the AC magnetic measurements reveal frequency dependence at low temperature suggesting slow relaxation of the magnetization. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - A European Journal 04/2015; 21(24). DOI:10.1002/chem.201500168 · 5.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A single crystal to single crystal transmetallation process takes place in the three-dimensional (3D) metal-organic framework (MOF) of formula Mg(II) 2 {Mg(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅45 H2 O (1; Me3 mpba(4-) =N,N'-2,4,6-trimethyl-1,3-phenylenebis(oxamate)). After complete replacement of the Mg(II) ions within the coordination network and those hosted in the channels by either Co(II) or Ni(II) ions, 1 is transmetallated to yield two novel MOFs of formulae Co2 (II) {Co(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅56 H2 O (2) and Ni2 (II) {Ni(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅ 54 H2 O (3). This unique postsynthetic metal substitution affords materials with higher structural stability leading to enhanced gas sorption and magnetic properties. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Angewandte Chemie International Edition 04/2015; 127(22). DOI:10.1002/anie.201501691 · 11.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The ligand 3-chloro-6-dipicolylamino-1,2,4,5-tetrazine (Cl-TTZ-dipica) 1, prepared by the direct reaction between 3,6-dichloro-1,2,4,5-tetrazine and di(2-picolyl)-amine, afforded a series of four neutral transition metal complexes formulated as [Cl-TTZ-dipica-MCl2]2, with M = Zn(II), Cd(II), Mn(II) and Co(II), when reacted with the corresponding metal chlorides. The dinuclear structure of the isostructural complexes was disclosed by single crystal X-ray analysis, clearly indicating the formation of [MII-(-Cl)2MII] motifs and the involvement of the amino nitrogen atom in semi-coordination with the metal centers, thus leading to distorted octahedral coordination geometries. Moreover, the chlorine atoms, either coordinated to the metal or as substituent on the tetrazine ring, engage respectively in specific anion- intramolecular and intermolecular interactions with the electron poor tetrazine units in the solid state, thus controlling the supramolecular architecture. Modulation of the emission properties is observed in the case of the Zn(II) and Cd(II) complexes when compared to the free ligand. A striking difference is observed in the magnetic properties of the Mn(II) and Co(II) complexes. An antiferromagnetic coupling takes place in the dimanganese(II) compound (J = -1.25 cm-1) while the Co(II) centers are ferromagnetically coupled in the corresponding complex (J = +0.55 cm-1), the spin Hamiltonian being defined as H = -JSA.SB.
    Dalton Transactions 04/2015; 44(19). DOI:10.1039/C5DT00550G · 4.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two types of oxalato-bridged heterometallic 3d-4f dodeca- and and hexanuclear compounds have been obtained by connecting six bi- and, respectively, trinuclear moieties through oxalato bridges arising from the slow decomposition of the L-ascorbic acid.
    Dalton Transactions 03/2015; 44(16). DOI:10.1039/C5DT00778J · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of the [Fe(III) (AA)(CN)4 ](-) complex anion as metalloligand towards the preformed [Cu(II) (valpn)Ln(III) ](3+) or [Ni(II) (valpn)Ln(III) ](3+) heterometallic complex cations (AA=2,2'-bipyridine (bipy) and 1,10-phenathroline (phen); H2 valpn=1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu(II) (valpn)Ln(III) (H2 O)3 (μ-NC)2 Fe(III) (phen)(CN)2 {(μ-NC)Fe(III) (phen)(CN)3 }]NO3 ⋅7 H2 O}n (Ln=Gd (1), Tb (2), and Dy (3)) and the trinuclear complex [Cu(II) (valpn)La(III) (OH2 )3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ]⋅NO3 ⋅H2 O⋅CH3 CN (4) were obtained with the [Cu(II) (valpn)Ln(III) ](3+) assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni(II) (valpn)Ln(III) (ONO2 )2 (H2 O)(μ-NC)3 Fe(III) (bipy)(CN)]⋅2 H2 O⋅2 CH3 CN}n (Ln=Gd (5), Tb (6), and Dy (7)) resulted with the related [Ni(II) (valpn)Ln(III) ](3+) precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu(II) (valpn)La(III) (OH2 )3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ](+) , nitrate counterions, and non-coordinate water and acetonitrile molecules. The heteroleptic {Fe(III) (bipy)(CN)4 } moiety in 5-7 acts as a tris-monodentate ligand towards three {Ni(II) (valpn)Ln(III) } binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu(II) Ln(III) (1-3) and Ni(II) Ln(III) (5-7) units, as well as through the single cyanide bridge between the Fe(III) and either Ni(II) (5-7) or Cu(II) (4) account for the overall ferromagnetic behavior observed in 1-7. DFT-type calculations were performed to substantiate the magnetic interactions in 1, 4, and 5. Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out-of-phase ac signals below 4.0 K in the lack of a dc field, the values of the pre-exponential factor (τo ) and energy barrier (Ea ) through the Arrhenius equation being 2.0×10(-12) s and 29.1 cm(-1) , respectively. In the case of 7, the ferromagnetic interactions through the double phenoxo (Ni(II) -Dy(III) ) and single cyanide (Fe(III) -Ni(II) ) pathways are masked by the depopulation of the Stark levels of the Dy(III) ion, this feature most likely accounting for the continuous decrease of χM T upon cooling observed for this last compound. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - A European Journal 02/2015; 21(14). DOI:10.1002/chem.201406088 · 5.73 Impact Factor

Publication Stats

17k Citations
2,281.81 Total Impact Points


  • 1987-2015
    • University of Valencia
      • • Inorganic Chemistry
      • • Facultad de Química
      Valenza, Valencia, Spain
  • 1992-2013
    • Pierre and Marie Curie University - Paris 6
      • Institut Parisien de Chimie Moléculaire (IPCM)
      Lutetia Parisorum, Île-de-France, France
    • University of Barcelona
      Barcino, Catalonia, Spain
  • 1998-2012
    • Universidad de La Laguna
      • • Department of Basic Physics II
      • • Department of Basic Physics
      • • Department of Inorganic Chemistry
      • • Faculty of Physics
      San Cristóbal de La Laguna, Canary Islands, Spain
  • 2005-2010
    • Università della Calabria
      • Dipartimento di Chimica e Tecnologie Chimiche - CTC
      Rende, Calabria, Italy
  • 2006
    • Nottingham Trent University
      Nottigham, England, United Kingdom
  • 2001-2002
    • University of Bergen
      • Department of Chemistry
      Bergen, Hordaland, Norway
    • Università degli Studi della Basilicata
      Potenza, Basilicate, Italy
  • 1996-1999
    • Philipps University of Marburg
      Marburg, Hesse, Germany
  • 1986-1994
    • University of Florence
      Florens, Tuscany, Italy
  • 1988
    • Università degli Studi di Messina
      Messina, Sicily, Italy
  • 1983
    • Université Paris-Sud 11
      Orsay, Île-de-France, France