Miguel Julve

University of Valencia, Valenza, Valencia, Spain

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Publications (480)1561.96 Total impact

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    ABSTRACT: Two new dinuclear copper(II) metallacyclophanes with 1,4-disubstituted 9,10-anthraquinonebis(oxamate) bridging ligands are reported that can reversibly take and release electrons at the redox-active ligand and metal sites, respectively, to give the corresponding mono- and bis(semiquinonate and/or catecholate) CuII2 species and mixed-valent CuII/CuIII and high-valent CuIII2 ones. Density functional calculations allow us to give further insights on the dual ligand- and metal-based character of the redox processes in this novel family of antiferromagnetically coupled di- copper(II) anthraquinophanes. This unique ability for charge storage could be the basis for the development of new kinds of molecular spintronic devices, referred to as molecular magnetic capacitors (MMCs).
    Chemistry 09/2014; · 5.93 Impact Factor
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    ABSTRACT: The six-coordinate cobalt(II) complex of formula [Co(tppz)2](tcm)2 exhibits a thermally induced spin-crossover behavior from a high spin (S = (3)/2) at higher temperatures to a low spin (S = (1)/2) at lower temperatures, with the low-spin phase being achieved at T ≤ 200 K.
    Inorganic chemistry. 09/2014;
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    ABSTRACT: Two new trinuclear copper(ii) complexes without end-capping ligands, (Bu4N)2[Cu(dmso)2{Cu(dnopba)(dmso)}2] () and (Bu4N)2[Cu(dmso)2{Cu(dcopba)(dmso)}2] () [dnopba = 4,5-dinitro-ortho-phenylenebis(oxamate), dcopba = 4,5-dichloro-ortho-phenylenebis(oxamate), Bu4N(+) = tetra-n-butylammonium and dmso = dimethylsulfoxide], were synthesized and their structures were determined by single crystal X-ray diffraction. The crystal structures of and consist of two outer bis(oxamato)(dmso)cuprate(ii) units which act as bidentate ligands toward a trans-bis(dmso)copper(ii) inner entity leading to centrosymmetric tricopper(ii) complexes with copper-copper separations across the oxamate bridges of 5.1916(3) () and 5.1776(3) Å (). The peripheral copper(ii) ions in and are five-coordinate in somewhat distorted square pyramidal environments with a dmso molecule filling the apical position whereas the inner copper(ii) ion is six-coordinate in an elongated octahedral environment with two dmso molecules in the axial sites. The investigation of their magnetic properties in the temperature range 2.0-300 K shows the occurrence of a strong intramolecular antiferromagnetic coupling between the copper(ii) ions through the oxamate bridges [J1 = -296(1) () and -334(1) cm(-1) (), the Hamiltonian being defined as Ĥ = -J1(ŜCu2·ŜCu1 + ŜCu2·ŜCu1')], which leads to a low-lying spin doublet at low temperatures. Density functional theory calculations (DFT) have been used to substantiate these magnetic couplings and also to analyse the influence exerted on these interactions by the type of substituent at the 4,5-positions from the phenylene ring of the bis(oxamate) ligand.
    Dalton Transactions 08/2014; · 3.81 Impact Factor
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    ABSTRACT: This work presents a series of layered systems based on phenylmalonate-containing copper(II) complexes and different coligands. Eight compounds [Cu(L)(Phmal)]n where L = pyrimidine (pym, 1) pyrazine (pyz, 2), 3-cyanopyridine (3-CNpy, 3), 4-cyanopyridine (4-CNpy, 4), 3-fluoropyridine (3-Fpy, 5), 3-chloropyridine (3-Clpy, 6), 3-bromopyridine (3-Brpy, 7) and 3-iodopyridine (3-Ipy, 8), have been synthesized and magneto-structurally characterized. The coligands selected not only modify the coordination environment of the metal ion, blocking or extending the polymerization, but also interact with the phenyl ring of the phenylmalonate ligand and dramatically affect the crystal packing through weak interactions. The crystallographic analysis reveals that compounds 1–8 present a corrugated square grid of carboxylate bridged copper(II) atoms where the pyridine ligands are alternatively located above and below each layer and, at the same time, inversely to the position of the phenyl group of the Phmal ligand. It is important to note that the pym and pyz ligands in 1 and 2 do not act as bridges between two copper atoms, whereas weak interactions between the cyano groups are also present in the structures of the complexes 3 and 4. The increase of the Van der Waals radius of the halogen along the series 5–8 accounts for the increase of the interlayer separation. Variable-temperature magnetic susceptibility measurements show the occurrence of different magnetic behaviours. Weak interactions are expected for the anti–syn carboxylate bridge in the out-of-plane configuration, that can be either ferro- or antiferromagnetic. Therefore, in this manuscript we shed light on the influence of the magneto-structural relationship in these square grid layered Cu(II) complexes.
    CrystEngComm 08/2014; 16(35). · 3.88 Impact Factor
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    ABSTRACT: Six new heterometallic cobalt(II)-lanthanide(III) complexes of formulas [Ln(bta)(H2O)2]2[Co(H2O)6]·10H2O [Ln = Nd(III) (1) and Eu(III) (2)] and [Ln2Co(bta)2(H2O)8]n·6nH2O [Ln = Eu(III) (3), Sm(III) (4), Gd(III) (5), and Tb(III) (6)] (H4bta = 1,2,4,5-benzenetretracaboxylic acid) have been synthesized and characterized via single-crystal X-ray diffraction. 1 and 2 are isostructural compounds with a structure composed of anionic layers of [Ln(bta)(H2O)2]n(n-) sandwiching mononuclear [Co(H2O)6](2+) cations plus crystallization water molecules, which are interlinked by electrostatic forces and hydrogen bonds, leading to a supramolecular three-dimensional network. 3-6 are also isostructural compounds, and their structure consists of neutral layers of formula [Ln2Co(bta)2(H2O)8]n and crystallization water molecules, which are connected through hydrogen bonds to afford a supramolecular three-dimensional network. Heterometallic chains formed by the regular alternation of two nine-coordinate lanthanide(III) polyhedra [Ln(III)O9] and one compressed cobalt(II) octahedron [Co(II)O6] along the crystallographic c-axis are cross-linked by bta ligands within each layer of 3-6. Magnetic susceptibility measurements on polycrystalline samples for 3-6 have been carried out in the temperature range of 2.0-300 K. The magnetic behavior of these types of Ln(III)-Co(II) complexes, which have been modeled by using matrix dagonalization techniques, reveals the lack of magnetic coupling for 3 and 4, and the occurrence of weak antiferromagnetic interactions within the Gd(III)-Gd(III) (5) and Tb(III)-Tb(III) (6) dinuclear units through the exchange pathway provided by the double oxo(carboxylate) and double syn-syn carboxylate bridges.
    Inorganic chemistry. 06/2014;
  • CrystEngComm 05/2014; · 3.88 Impact Factor
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    ABSTRACT: A novel cobalt(II) complex of formula [Co2(cbut)(H2O)3]n (1) (H4cbut = 1,2,3,4-cyclobutanetetracarboxylic acid) has been synthesized under hydrothermal conditions and its crystal structure has been determined by means of synchrotron radiation and neutron powder diffraction. The crystal structure of 1 consists of layers of cobalt(II) ions extending in the bc-plane which are pillared along the crystallographic a-axis through the skeleton of the cbut(4-) ligand. Three crystallographically independent cobalt(II) ions [Co(1), Co(2), and Co(3)] occur in 1. They are all six-coordinate with four carboxylate-oxygens [Co(1)-Co(3)] and two cis-[Co(1)] or trans-water molecules [Co(2) and Co(3)] building distorted octahedral surroundings. Regular alternating double oxo(carboxylate) [between Co(1) and Co(1a)] and oxo(carboxylate) plus one aqua and a syn-syn carboxylate bridges [between Co(1) and Co(2)] occur along the crystallographic b-axis, the values of the cobalt-cobalt separation being 3.1259(8) and 3.1555(6) Å, respectively. These chains are connected to the Co(3) atoms through the OCO carboxylate along the [01̅1] direction leading to the organic-inorganic bc-layers with Co(1)-OCO(anti-syn)-Co(3) and Co(2)-OCO(anti-anti)-Co(3) distances of 5.750(2) and 4.872(1) Å. The shortest interlayer cobalt-cobalt separation through the cbut(4-) skeleton along the crystallographic a-axis is 7.028(2) Å. Variable-temperature magnetic susceptibility measurements show the occurrence of antiferromagnetic ordering with a Néel temperature of 5.0 K, followed by a field-induced ferromagnetic transition under applied dc fields larger than 1500 Oe. The magnetic structure of 1 has been elucidated at low temperatures in zero field by neutron powder diffraction measurements and was found to be formed by ferromagnetic chains running along the b-axis which are antiferromagnetically coupled with the Co(3) ions through the c-axis giving rise to noncompensated magnetic moments within each bc-layer (ferrimagnetic plane). The occurrence of an antitranslation operation between these layers produces a weak interlayer antiferromagnetic coupling along the a-axis which is overcome by dc fields greater than 1500 Oe resulting in a phase transition toward a ferromagnetic state (metamagnetic behavior).
    Inorganic Chemistry 05/2014; · 4.59 Impact Factor
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    ABSTRACT: A novel series of heteroleptic copper(II) compounds of formulas {[Cu2(μ-H2O)(μ-pz)2(μ-bpm)(ClO4)(H2O)]ClO4·2H2O}n (1), {[Cu2(μ-H2O)(μ-3-Mepz)2(μ-bpm)](ClO4)2·2H2O}n (2), and {[Cu2(μ-OH)(μ-3,5-Me2pz)(μ-bpm)(H-3,5-Me2pz)2](ClO4)2}n (3) [bpm = 2,2'-bipyrimidine, Hpz = pyrazole, H-3-Mepz = 3-methylpyrazole, and H-3,5-Me2pz = 3,5-dimethylpyrazole] have been synthesized and structurally characterized by X-ray diffraction methods. The crystal structures of 1 and 2 consist of copper(II) chains with regular alternating bpm and bis(pyrazolate)(aqua) bridges, whereas that of 3 is made up of copper(II) chains with regular alternating bpm and (pyrazolate)(hydroxo) bridges. The copper centers are six- (1) or five-coordinate (2) in axially elongated, octahedral (1) or square-pyramidal (2) environments in 1 and 2, whereas they are five-coordinate in distorted trigonal-bipyramidal surroundings in 3. The values of the copper-copper separations across the bpm/pyrazolate bridges are 5.5442(7)/3.3131(6) (1), 5.538(1)/3.235(1) (2), and 5.7673(7)/3.3220(6) Å (3). The magnetic properties of 1-3 have been investigated in the temperature range of 25-300 K. The analysis of their magnetic susceptibility data through the isotropic Hamiltonian for an alternating antiferromagnetic copper(II) chain model [H = -J∑i=1-n/2 (S2i·S2i-1 + αS2i·S2i+1), with α = J'/J and Si = SCu = 1/2] reveals the presence of a strong to moderate antiferromagnetic coupling through the bis(pyrazolate)(aqua) [-J = 217 (1) and 215 cm(-1) (2)] and (pyrazolate)(hydroxo) bridges [-J = 153 cm(-1) (3)], respectively, whereas a strong to weak antiferromagnetic coupling occurs through the bis-bidentate bpm [-J' = 211 (1), 213 (2), and 44 cm(-1) (3)]. A simple orbital analysis of the magnetic exchange interaction within the bpm- and pyrazolate-bridged dicopper(II) fragments of 1-3 visualizes the σ-type pathways involving the (dx(2)-y(2)) (1 and 2) or d(z(2)) (3) magnetic orbitals on each metal ion, which account for the variation of the magnetic properties in these three novel examples of one-dimensional copper(II) compounds with regular alternating intrachain antiferromagnetic interactions.
    Inorganic Chemistry 05/2014; · 4.59 Impact Factor
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    ABSTRACT: New examples of cyanido-bearing cobalt(III/II) complexes have been obtained by treatment of CoCl2·6H2O with bidentate nitrogen donors and potassium cyanide in a methanol/water mixture. Depending on the chelating ligand, the cobalt(III) complexes PPh4[Co(en)(CN)4] (1, en = ethylenediamine), PPh4[Co(ampy)(CN)4]·1.5H2O [2, ampy = 2-(aminomethyl)pyridine], and PPh4[Co(phen)(CN)4]·CH3OH·0.25H2O (3, phen = 1,10-phenanthroline) and the cobalt(II) complex PPh4[Co(dmphen)(CN)3]·3H2O (4, dmphen = 2,9-dimethyl-1,10-phenanthroline) were obtained. The complexes were characterized by single-crystal X-ray diffraction and variable-temperature magnetic measurements. They are all mononuclear species with six-coordinate cobalt(III) (1–3) and five-coordinate cobalt(II) centers (4), and two nitrogen atoms from each bidentate ligand (1–4) and four (1–3) or three cyanide carbon atoms (4) build somewhat distorted octahedral (1–3) or square-pyramidal (4) surroundings. Complexes 1–3 are diamagnetic cobalt(III) compounds, whereas 4 is a low-spin cobalt(II) complex that exhibits Curie behavior in the temperature range 10–300 K. The g values of the X-band electron paramagnetic resonance (EPR) spectrum of 4 both in the solid state and in dichloromethane solution at 4.0 K (g⟂ = 2.28 > g∥ = 2.0) reveal that its unpaired electron is defined by a d-type orbital. Complexes 1–4 can be viewed as new metalloligands for metal assemblies.
    Berichte der deutschen chemischen Gesellschaft 05/2014; · 2.94 Impact Factor
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    ABSTRACT: A new chloro-bridged heterobimetallic Cu(ii)Re(iv) chain of formula {Cu(pyim)(Him)2ReCl6}n·MeCN (·MeCN) has been prepared and magnetostructurally characterised. Compound is the first example of the [Re(IV)Cl6](2-) anion acting as a metalloligand towards a paramagnetic metal ion.
    Chemical Communications 04/2014; · 6.38 Impact Factor
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    ABSTRACT: The design and synthesis of novel examples of multifunctional magnetic materials based on the so-called coordination polymers (CPs) have become very attractive for chemists and physicists due to their potential applications in nanoscience and nanotechnology. However, their preparation is still an experimental challenge, which requires a deep knowledge of coordination chemistry and large skills in organic chemistry. The recent advances in this field using a molecular-programmed approach based on rational self-assembly methods which fully exploit the versatility of the coordination chemistry of the barely explored and evergreen family of N-substituted aromatic oligo(oxamato) ligands are presented in this feature article. These exploratory studies have revealed a wide variety of interesting multifunctional magnetic materials such as optically-active chiral and luminescent magnets or dynamic porous magnets as candidates for chemical sensing. Our feeling, however, is that we have only scratched the surface of the topic and that there are many more exciting brand-new molecule-based materials waiting to be discovered.
    Chemical Communications 04/2014; · 6.38 Impact Factor
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    ABSTRACT: The enantiopure radical cation salts [(S,S)-DM-BEDT-TTF]4[ReCl6] ([(S,S)-1]4[ReCl6]) and [(R,R)-DM-BEDT-TTF]4[ReCl6] ([(R,R)-1]4[ReCl6]) [DM-BEDT-TTF = dimethylbis(ethylenedithio)tetrathiafulvalene] have been prepared by electrocrystallization of the chiral precursor DM-BEDT-TTF in the presence of NBu4[ReCl5(pyrazine)] (NBu4 = tetra-n-butylammonium cation; pyz = pyrazine) as supporting electrolyte. The single-crystal X-ray analysis shows that the compounds crystallize in the triclinic system, non-centrosymmetric space group P1, and that the donors arrange in parallel columns. The four independent donor molecules possess approximate charges of +1, +1/2, +1/2 and 0, according to the structural parameter analysis and band-structure calculations, which also support the semiconducting behaviour of the materials. The rhenium(IV) ion in both compounds is six-coordinate with six chloro atoms that describe a slightly distorted octahedral environment with Re–Cl distances that cover the short range 2.348–2.374 Å. Magnetic measurements on polycrystalline samples of [(S,S)-1]4[ReCl6] and [(R,R)-1]4[ReCl6] have been investigated in the temperature range 2–295 K. They are practically identical and confirm the presence of high-spin S = 3/2 [ReCl6]2– isolated monomers together with a Pauli paramagnetism, typical of this kind of system. The magnetic susceptibility data are thoroughly reproduced over the whole temperature range with a simple model of isolated S = 3/2 ions with a zero-field splitting plus a temperature-independent paramagnetism (TIP), and the best-fit parameters being gRe = 1.875(2), |D| = 4.50(3) cm–1 and TIP = 3630(20)×10–6 cm3 mol–1 (2D is the energy gap between the MS = ±3/2 and MS = ±1/2 Kramers doublets).
    Berichte der deutschen chemischen Gesellschaft 04/2014; · 2.94 Impact Factor
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    ABSTRACT: New and versatile bis(oxamato)palladate(II) complexes (I) are synthesized and investigated for both Suzuki and Heck coupling reactions in molten tetra-n-butylammonium bromide as ionic liquid.
    ChemInform 01/2014; 45(3).
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    ABSTRACT: Four new heterometallic 3d–4f complexes have been obtained using bi- and trinuclear building blocks: 1∞[Ni(L1)Gd(NO3)3(azbbpy)]·CH3CN (1), [Zn(L1)Eu(NO3)3(azbbpy)]·H2O (2), 1∞[(CuL2)2Gd(NO3)2(dca)] 3 and 1∞[(NiL2)2Dy(H2O)4(oxy-bbz)]NO3·3H2O (4), [H2L1 = 1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol), H2L2 = 2,6-di(acetoacetyl)pyridine, azbbpy = 1,3-bis(4-pyridyl)azulene, dca− = dicyanamide anion, and oxy-bbz = the dianion of the 4,4′-oxy-bis(benzoic) acid]. 1 and 2 represent the first complexes containing 1,3-bis(4-pyridyl)azulene as a ligand. 1, 3, and 4 are one-dimensional coordination polymers constructed from heterometallic nodes connected by the exo-dentate ligands. Helical chains are assembled in the case of 4. The analysis of the packing diagram for 1 reveals the occurrence of π–π stacking interactions established between the azulene rings from neighboring chains, which lead to supramolecular layers. The magnetic properties of 3 in the temperature range 1.9–300 K have been investigated. Intra-node ferromagnetic interactions are established between the CuII and GdIII ions (J = +2.7 cm−1, Ĥ = −J(ŜCu·ŜGd + ŜCu·ŜGd).
    CrystEngComm 01/2014; 16(3):319-327. · 3.88 Impact Factor
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    ABSTRACT: Graphical abstract The complex formation of Co(II) and Cu(II) ions with the monoethyl ester derivative of the N-(4-carboxyphenyl)oxamic acid yielded different coordination polymers whose structures and variable-temperature magnetic study are presented here.
    Polyhedron 01/2014; 81:105–114. · 2.05 Impact Factor
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    ABSTRACT: There is plenty of room at the bottom: A gap in the literature of molecular nanomagnets has been filled with the preparation of the first mononuclear manganese(III) complex exhibiting a slow relaxation of the magnetization, that is, a species with a single slow-relaxing, highly anisotropic Mn(III) ion, as confirmed by very low-temperature micro-SQUID magnetization and high-field EPR spectroscopic measurements (N blue, O red, Mn purple, Cl green).
    Angewandte Chemie International Edition 11/2013; · 11.34 Impact Factor
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    ABSTRACT: The exchange mechanism and magnetic structure of the organic-inorganic layered molecule-based magnet [Co2(bta)]n (1) (H4bta =1,2,4,5-benzenetetracarboxylic acid) have been investigated through variable-temperature magnetic susceptibility measurements and supported with a series of neutron diffraction experiments. Cryomagnetic studies have shown an antiferromagnetic ordering at a transition temperature of 16 K that is followed by the appearance of a weak ferromagnetism below 11 K. The weak antiferromagnetic interlayer interaction plays an important role in this system in spite of the long interlayer separation. A ferromagnetic ordering is induced by applied magnetic fields greater than 1800 G (metamagnetic behavior), and a slow magnetic relaxation from this ferromagnetic phase to the antiferromagnetic one is observed. The magnetic structure of 1 has been elucidated at low temperatures in zero field by neutron powder diffraction measurements and was found to be of antiferromagnetic nature with the local cobalt(II) spins (magnetic moments) being aligned ferromagnetically in the ac plane and antiferromagnetically coupled along the crystallographic b axis. No evidence for a long-range spontaneous ferromagnetic component below 11 K was observed in the neutron experiment.
    Inorganic Chemistry 10/2013; · 4.59 Impact Factor
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    ABSTRACT: The synthesis and structural characterization of five Cu(II)–Ln(III) heteronuclear metal–organic frameworks of formula {[Ln4Cu4(H2O)26(bta)5]·mH2O}n and {[Ln4Cu4(H2O)24(bta)5]·pH2O}n [Ln = LaIII (1A/1B), CeIII (2A/2B), PrIII (3A/3B), NdIII (4A/4B) and SmIII (5A/5B) with m/p = 20 (1A)/16 (1B), 18 (2A)/16 (2B), 14 (3A)/16 (3B), 22 (4A)/16 (4B) and 21 (5A)/14 (5B); H4bta =1,2,4,5-benzenetetracarboxylic acid (1–5)] have been performed. These compounds present a single-crystal to single-crystal phase transition from expanded A phases toward the B shrinking networks, which is triggered only in the presence of a dry environment. This phase transition is accompanied by a compression of the crystallographic b-axis in the range 2.4 to 2.8 Å with the consequent decrease of the unit cell volume from 9.5% to 12%. The isomorphous crystal structures of 1A–5A can be described as two crystallographically independent [Cu(II)–Ln(III)] heterometallic dinuclear units which are connected through two crystallographically independent bta4– ligands in the ac-plane, leading to 4,4-rectangular grids. These layers are connected along the crystallographic b-axis, through a pillaring bta4– group. The phase transition implies a change of the coordination mode of the bta4– pillar from bis-monodentate (1A–5A) to tetrakis-monodentate (1B–5B). Magnetic susceptibility measurements of polycrystalline samples of 1A–5A in the temperature range 2.0–300 K have in common the decrease of the χMT product with T which in the case of 1A is due to weak antiferromagnetic interactions between the copper(II) ions through the bta4– skeleton, the LaIII cation being diamagnetic [J = −3.5 cm–1 with the Hamiltonian defined H = −JSCu1·SCu2]. For the 2A–5A compounds, the additional exchange interaction between CuII and the paramagnetic LnIII is masked by the crystal field effects (which partially removes the 2J + 1 degeneracy of the 2S+1LJ free-ion ground state in zero magnetic field) (2A–5A) and the thermal population of excited free-ion states (5A).
    Crystal Growth & Design 10/2013; 13(11):4735–4745. · 4.69 Impact Factor
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    ABSTRACT: By using Vitamin B6 in its monodeprotonated pyridoxine form (PN-H) [PN = 3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridine], two tetranuclear compounds of formula [Mn4(PN-H)4(CH3CO2)3Cl2]Cl·2CH3OH·2H2O (1) and [Cu4(PN-H)4Cl2(H2O)2]Cl2 (2) have been synthesized and magneto-structurally characterized. 1 crystallizes in the triclinic system with space group P1̅ whereas 2 crystallizes in the orthorhombic system with Fdd2 as space group. They exhibit Mn(II)2Mn(III)2 (1) and Cu(II)4 (2) cubane cores containing four monodeprotonated pyridoxine groups simultaneously acting as chelating and bridging ligands (1 and 2), three bridging acetate ligands in the syn-syn conformation (1), and two terminally bound chloride anions (1 and 2) plus two coordinated water molecules (2). The electroneutrality is achieved by the presence of chloride counterions in both compounds. Tri- [Mn(1) and Mn(3)] and divalent [Mn(2) and Mn(4)] manganese centers coexist in 1, all being six-coordinate with distorted Mn(1/3)O6 and Mn(2/4)O5Cl octahedral surroundings, respectively, the equatorial Mn-O bonds being about 0.2 Å shorter at the former ones. The two crystallographically independent copper(II) ions in 2 are five-coordinate in somewhat distorted CuO5 [Cu(1)] and CuO4Cl [Cu(2)] square pyramidal geometries. The values of the intracore metal-metal separation cover the ranges 3.144(1)-3.535(1) (1) and 2.922(6)-3.376(1) Å (2). The magnetic properties of 1 and 2 were investigated in the temperature range 1.9-300 K, and they correspond to an overall antiferromagnetic behavior with susceptibility maxima at 5.0 (1) and 65.0 K (2). The analysis of the magnetic susceptibility data showed the coexistence of intracore antiferro- and ferromagnetic interactions in the two compounds. Their values compare well with those existing in the literature for the parent systems.
    Inorganic Chemistry 09/2013; · 4.59 Impact Factor
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    ABSTRACT: Three isomorphous two-dimensional (2D) coordination polymers of general formula {[Ni(II)(valpn)Ln(III)(NO3)(H2O)(μ-NC)4W(IV)(bipy)(CN)2]·xH2O·yCH3CN}n have been synthesized by reacting Ph4P[W(V)(CN)6(bipy)] with the heterodinuclear [Ni(II)Ln(III)(valpn)(O2NO)3] complexes [H2valpn = 1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol), bipy = 2,2'-bipyridine, and Ln = Gd (1), Dy (2), and Tb (3) with x = 2 (1), 3.9 (2), and 3.35 (3) and y = 2.50 (1), 2 (2), and 1.8 (3)]. Their crystal structures consist of [Ni(II)Ln(III)] 3d-4f nodes which are connected by [W(IV)(bipy)(CN)6](2-) diamagnetic linkers resulting from the reduction of W(V) to W(IV) during the reaction process. The Ni(II) and Ln(III) ions occupy the inner and outer coordination sites of the dideprotonated valpn ligand, respectively, and they are doubly bridged by the phenoxo oxygen atoms of such a ligand. The value of Ni(II)···Ln(III) separation through this bridge is 3.4919(10) (1), 3.4760(10) (2), and 3.4799(9) (3) Å, and those of the angles at the bridgehead phenoxo atoms are 106.6(2) and 107.3(2) (1), 106.9(2), and 107.8(2) (2) and 106.5(2)-106.8(2)° (3). Each W(IV) is eight-coordinated with a bidentate bipy molecule and six cyanide-carbon atoms building a somewhat distorted square antiprism environment. The rare-earth cations are nine-coordinated, the donor atoms describing a monocapped square antiprism for 1 and 3 and a tricapped trigonal prism for 2. Magnetic susceptibility measurements in the temperature range 1.9-300 K show the occurrence of ferromagnetic interactions between the Ni(II) and Ln(III) ions in 1-3. Frequency-dependent alternating susceptibility signals were observed for the Dy(III) derivative below 8.0 K under an applied dc field of 2500 G indicating the presence of slow magnetic relaxation with values of the pre-exponential factor (τ0) and energy barrier (E(#)) of ca. 5.7 × 10(-8) s and 15.9 cm(-1), respectively. Complex 2 constitutes the first example of a 2D 3d-4f heterobimetallic single molecule magnet (SMM).
    Inorganic Chemistry 09/2013; · 4.59 Impact Factor

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2k Citations
1,561.96 Total Impact Points


  • 1985–2014
    • University of Valencia
      • • Instituto de Ciencia Molecular (ICMol)
      • • Inorganic Chemistry
      • • Departamento de Química Orgánica
      • • Facultad de Química
      Valenza, Valencia, Spain
  • 2013
    • Federal University of Minas Gerais
      • Departamento de Química
      Cidade de Minas, Minas Gerais, Brazil
  • 2010–2013
    • UPMC
      Pittsburgh, Pennsylvania, United States
    • Polytech Paris-UPMC
      Lutetia Parisorum, Île-de-France, France
  • 2004–2013
    • University of Bucharest
      • Faculty of Chemistry
      Bucharest, Bucuresti, Romania
  • 2003–2012
    • University of the Republic, Uruguay
      • Facultad de Química
      Montevideo, Departamento de Montevideo, Uruguay
  • 2000–2012
    • Universidad de La Laguna
      • • Department of Basic Physics II
      • • Facultad de Física
      San Cristóbal de La Laguna, Canary Islands, Spain
  • 1996–2012
    • Università della Calabria
      • Dipartimento di Chimica e Tecnologie Chimiche - CTC
      Rende, Calabria, Italy
  • 1994–2012
    • Pierre and Marie Curie University - Paris 6
      • Institut Parisien de Chimie Moléculaire (IPCM)
      Paris, Ile-de-France, France
  • 2011
    • Syracuse University
      • Department of Chemistry
      Syracuse, NY, United States
  • 2008
    • Justus-Liebig-Universität Gießen
      • Institut für Anorganische und Analytische Chemie
      Gießen, Hesse, Germany
  • 2007
    • University of Concepción
      • Facultad de Ciencias Químicas
      Concepción, Region del Biobio, Chile
  • 2006
    • Nottingham Trent University
      Nottigham, England, United Kingdom
    • Academy of Sciences of Moldova
      • Institute of Applied Physics
      Chişinău, Municipiul Chisinau, Moldova
  • 2001
    • Universidad del País Vasco / Euskal Herriko Unibertsitatea
      • Departamento de Química Inorgánica
      Bilbao, Basque Country, Spain
    • Università degli Studi della Basilicata
      Potenza, Basilicate, Italy
  • 1993–2001
    • University of Barcelona
      • • Departament de Química Inorgànica
      • • Department of Crystallography, Mineralogy and Mineral Deposits
      Barcelona, Catalonia, Spain
    • Polytechnical University of Valencia
      • Department of Chemistry
      Valencia, Valencia, Spain
  • 1999
    • Philipps University of Marburg
      Marburg, Hesse, Germany
  • 1984
    • Université Paris-Sud 11
      Orsay, Île-de-France, France