J Vidal-Gancedo

Publications (118)28.02 Total impact

• Chapter: Intramolecular Electron Transfer in Organic Molecules. Molecular Nanowires

  D. Ruiz-Molina, J. Vidal-Gancedo, J. Sedo, I. Ratera, J. Veciana, C. Rovira
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  ABSTRACT: In the last few years, considerable interest is being devoted to the obtaining of molecular wires that exhibit intramolecular electron transfer phenomena [1–4]. The interest arises from the potential use of such systems on integrated molecular devices [5,6] and the technical advantages that can be derived from there. First, the ever-increasing miniaturization of the architectural components of microchips reverts in the reduction size of computational systems. Second, time for an electron to travel through the circuit can be minimized using molecular-scale electronic architectures, which operate at far greater speeds. The main drawbacks are the high conformational requirements that the molecule to be used must fulfill. For instance, an average interelectrode distance of 100 Å obtained using “engineering-down” techniques; i.e., litographic techniques, requires the synthesis of molecular systems that in addition to a p-conjugated pathway, have similar dimensions to the interelectrode distance and restricted conformational geometries. One of the few examples of such exigent conformational systems has been reported by Gourdon et al. [7]. Another approach, which overcomes such difficulties, is the use of self-assembling techniques. Indeed, using this technique Tour et al. [8] were able to study quantitatively the conductance of a single benzene-1,4-dithiol molecule located between two gold nanoelectrodes. These results aim us to expect practical applications for this kind of systems in the near future. However, if a truly molecular computational device is to be achieved, new systematic studies that allow us to obtain rules for the prediction and control of the electron propagation in molecular wires are highly required.
  06/2011: pages 125-138;
• Article: Synthesis, structural and magnetic properties of a series of copper(II) complexes containing a monocarboxylated perchlorotriphenylmethyl radical as a coordinating open-shell ligand.

  D Maspoch, D Ruiz-Molina, K Wurst, J Vidal-Gancedo, C Rovira, J Veciana
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  ABSTRACT: A series of complexes of copper(II)-containing a perchlorotriphenylmethyl radical functionalized with a carboxylic group as a new ligand is reported. The compounds [Cu(PTMMC)(2)(L)(3)](PTMMC = (tetradecachloro-4-carboxytriphenyl)methyl radical; L =(1) H(2)O, (2) pyrimidine and ethanol or (3) pyridine), [Cu(2)(PTMMC)(2)(MeCOO)(2)(H(2)O)(2)](4) and [Cu(HPTMMC)(2)(L)(3)](HPTMMC =alpha-H-(tetradecachlorotriphenyl)methane-4-carboxylic acid; L = pyridine)(5) were structurally characterized. In complexes 1, 2, 3, and 5, the copper(II) ion is coordinated to two PTMMC (or HPTMMC) units in a slightly distorted square planar surrounding, while 4 shows a paddle-wheel copper(II) dimer structure, where each Cu metal ion has four O atoms of different carboxylate groups, two of them belonging to two PTMMC radicals. The copper(II)-radical exchange couplings are antiferromagnetic for complexes 1, 2 and 3. A linear three-spin model was applied to complexes 1, 2 and 3 to give J/k(B)=-24.9, -15.0 and -20.7 K, respectively. Magnetic properties of 4 show that it is one of the scarce examples of a spin-frustrated system composed of organic radicals and metal ions. In this case, experimental data were fitted to a magnetic model based on a symmetrical butterfly arrangement to give a copper(II)-copper(II) exchange coupling of J/k(B)=-350.0 K and a copper(II)-radical exchange coupling of J/k(B)=-21.3 K, similar to that observed for the copper(II)-radical interactions in complexes, and.
  Dalton Transactions 05/2004; · 3.84 Impact Factor
• Article: Bulk spontaneous magnetization in the new radical cation salt TM-TTF[Cr(NCS)(4)(isoquinoline)(2)] (TM-TTF = tetramethyltetrathiafulvalene).

  M Mas-Torrent, S S Turner, K Wurst, J Vidal-Gancedo, X Ribas, J Veciana, P Day, C Rovira
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  ABSTRACT: A new organic-inorganic hybrid salt [TM-TTF][Cr(NCS)(4)(isoquinoline)(2)] (1) (TM-TTF = Tetramethyltetrathiafulvalene) has been synthesized. Compound 1 crystallizes in the triclinic P space group with a = 8.269(1), b = 10.211(2), and c = 11.176(2) A, alpha = 89.244(9), beta = 88.114(6), and gamma = 74.277(7) degrees, V = 907.6(3) A(3), and Z = 1. The crystal structure was resolved in the temperature range between 223 and 123 K, showing that changes in the crystal structure at low temperature result in stronger interactions between anions and cations. The packing of 1 consists of mixed anion-cation layers in the bc plane containing S.S and pi-pi anion-cation interactions, the layers being connected by very short S.S contacts between anions and cations. Magnetic measurements in a small external field show bulk spontaneous magnetization with a T(c) of 6.6 K consistent with the presence of weakly coupled ferrimagnetic order in compound 1. The EPR measurements also demonstrate the interaction between the d and pi electrons and the presence of an internal magnetic field brought about by the magnetic ordering.
  Inorganic Chemistry 12/2003; 42(23):7544-9. · 4.60 Impact Factor
• Article: Isolation and characterization of four isomers of a C(60) bisadduct with a TTF derivative. Study of their radical ions.

  M Mas-Torrent, R A Rodríguez-Mias, M Solà, M A Molins, M Pons, J Vidal-Gancedo, J Veciana, C Rovira
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  ABSTRACT: A family of triads composed of C(60) attached by a rigid spacer to two identical TTF moieties has been synthesized, and some of the isomers have been isolated and characterized by UV-vis spectroscopy, LDI-TOF-MS, and HMBC NMR spectroscopy. AM1 semiempirical calculations of the dipolar moments and the heats of formation of the different isomers have been carried out in order to verify their assignments. Oxidation and reduction of the triads affords the derived radical ion systems, TTF(+*)-C(60)-TTF(+*) and TTF-C(60)(-*)-TTF, which were studied by EPR spectroscopy. Spin density distributions of these radical cations and radical anions show that the unpaired electron is located mainly on the TTF and fullerene moieties, respectively. However, while the EPR signals obtained from the radical cations are very similar for all the isomers, the structured signals observed for the radical anions arising from the coupling of the unpaired electron with the hydrogen atoms of the methylene bridges in the spacer show that there is a strong influence of the isomerism on the spin distribution. Importantly, the theoretical calculations of the spin density distributions of the radical anions fit well with the experimental EPR results.
  The Journal of Organic Chemistry 02/2002; 67(2):566-75. · 4.45 Impact Factor
• Article: Hybrid molecular materials based upon organic pi-electron donors and metal complexes. Radical salts of bis(ethylenethia)tetrathiafulvalene (BET-TTF) with the octahedral anions hexacyanoferrate(III) and nitroprusside. The first kappa phase in the BET-TTF family.

  M Clemente-León, E Coronado, J R Galán-Mascarós, C Giménez-Saiz, C J Gómez-García, E Ribera, J Vidal-Gancedo, C Rovira, E Canadell, V Laukhin
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  ABSTRACT: The synthesis, structure, and physical characterization of two new radical salts formed with the organic donor bis(ethylenethia)tetrathiafulvalene (BET-TTF) and the octahedral anions hexacyanoferrate(III), [Fe(CN)(6)](3-), and nitroprusside, [Fe(CN)(5)NO](2-), are reported. These salts are (BET-TTF)(4)(NEt(4))(2)[Fe(CN)(6)] (1) (monoclinic space group C2/c with a = 38.867(7) A, b = 8.438(8) A, c = 11.239(6) A, beta = 90.994(9) degrees, V = 3685(4) A(3), Z = 4) and (BET-TTF)(2)[Fe(CN)(5)NO].CH(2)Cl(2) (2) (monoclinic space group C2/c with a = 16.237(6) A, b = 18.097(8) A, c = 12.663(7) A, beta = 106.016(9) degrees, V = 3576(3) A(3), Z = 4). In salt 1 the organic BET-TTF molecules are packed in orthogonal dimers, forming the first kappa phase observed for this donor. The analysis of the bond distances and the electronic and IR spectra suggests a degree of ionicity of 1/4 per BET-TTF molecule, in agreement with the stoichiometry of the salt. The electrical properties show that 1 is a semiconductor with a high room-temperature conductivity (11.6 S cm(-1)) and a low activation energy (45 meV), in agreement with the band structure calculations. The magnetic susceptibility of 1 shows, besides the paramagnetic contribution from the anion, a temperature-independent paramagnetism (TIP) of the Pauli type due to the electronic delocalization observed at high temperatures in the organic sublattice. This Pauli type paramagnetism is confirmed by the ESR spectra that also show a Dysonian line when the magnetic field is parallel to the conducting plane, typical of metallic and highly conducting systems. Salt 2 presents an unprecedented packing of the organic molecules that form zigzag tunnels where the anions and the solvent molecules are located. The stoichiometry indicates that all the BET-TTF molecules bear a charge of +1, and accordingly, 2 behaves as a semiconductor with a very low room-temperature conductivity. The magnetic properties of this salt indicate that the unpaired electrons on the organic molecules are strongly antiferromagnetically coupled, giving rise to a diamagnetic behavior of 2, as the nitroprusside anion is also diamagnetic.
  Inorganic Chemistry 08/2001; 40(14):3526-33. · 4.60 Impact Factor
• Article: Influence of topology on the long-range electron-transfer phenomenon.

  C Rovira, D Ruiz-Molina, O Elsner, J Vidal-Gancedo, J Bonvoisin, J P Launay, J Veciana
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  ABSTRACT: Intramolecular electron-transfer phenomena in the radical anions derived from the partial reduction of diradicals (E,E)-p-divinylbenzene-beta,beta'-ylene bis(4-tetradecachlorotriphenylmethyl) diradical (1) and (E,E)-m-divinylbenzene-beta,beta'-ylene bis(4-tetradecachlorotriphenylmethyl) diradical (2) have been studied by optical and ESR spectroscopy. The synthetic methodology used allows for complete control of the geometry of diradicals 1 and 2, which have para and meta topologies, respectively, as well as of their E/Z isomerism. This fact is used to show the influence of the different topologies on the ease of electron transfer, which is larger for the para than for the meta isomer, in which a small or negligible electronic coupling is observed. A related monoradical compound (E)-bis(pentachlorophenyl)[4-(4-bromophenyl-beta-styryl)-2,3,5,6-tetrachlorophenyl]-methyl radical (3), which has only one such redox site, has also been obtained and studied for comparison purposes.
  Chemistry 02/2001; 7(1):240-50. · 5.93 Impact Factor
• Article: Transmission of Magnetic Interactions through an Organometallic Coupler: A Novel Family of Metallocene-Substituted alpha-Nitronyl Aminoxyl Radicals.

  O. Jürgens, J. Vidal-Gancedo, C. Rovira, K. Wurst, C. Sporer, B. Bildstein, H. Schottenberger, P. Jaitner, J. Veciana
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  ABSTRACT: The capability of metallocene bridges as new organometallic magnetic couplers is evaluated by studying the family of diradicals 2 (M = Fe, Ru) consisting of two purely organic alpha-nitronyl aminoxyl radicals connected by a 1,1'-metallocenylene bridge. Preliminary studies performed with 2-metallocenyl-alpha-nitronyl aminoxyl monoradicals 1 (M = Fe, Ru, Os), as reference compounds, show the presence of a small spin density on the central metal of the metallocenes. This fact makes the metallocene units effective bridges to transmit magnetic interactions by a spin polarization mechanism. The study of the magnetic properties of diradicals 2 in the solid state and in diluted frozen solutions reveals the existence of an intramolecular antiferromagnetic exchange interaction between the radical subunits whose strength is highly dependent on the molecular conformation adopted by the diradical. As shown by crystal data and by ESR measurements, an intramolecular hydrogen bond between the two radical units forces the molecule to adopt a cisoid molecular conformation, which determines that the magnetic interaction occurs by a direct through-space interaction between the two SOMOs of the two radical units along with the classical spin polarization mechanism through the sigma-bonds of the metallocene unit. Lattice constants for both structures are as follows: 1 (M = Fe), C(17)H(21)FeN(2)O(2), a = 7.170(1) Å, b = 10.135(2) Å, c = 10.683(2) Å, alpha = 88.88(3) degrees, beta = 83.42(3) degrees, gamma = 79.75(3) degrees, triclinic, P&onemacr;, Z = 2; 2 (M = Fe), C(24)H(32)FeN(4)O(4), a = 11.848(3) Å, b = 11.785(2) Å, c = 17.728(4) Å, beta = 106.25(2) degrees, monoclinic, P2(1)/n, Z = 4.
  Inorganic Chemistry 10/1998; 37(18):4547-4558. · 4.60 Impact Factor
• Article: A new organic conductor and a novel structural phase transition in the BEDT-TTF trihalide family

  E. Laukhina, J. Vidal-Gancedo, S. Khasanov, V. Tkacheva, L. Zorina, R. Shibaeva, J. Singleton, R. Wojciechowski, J. Ulanski, V. Laukhin, J. Veciana, C. Rovira
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  ABSTRACT: Times Cited: 14
  12:1205-1210.
• Article: A molecular multiproperty switching array based on the redox behavior of a ferrocenyl polychlorotriphenyhnethyl radical

  C. Sporer, I. Ratera, D. Ruiz-Molina, Y. X. Zhao, J. Vidal-Gancedo, K. Wurst, P. Jaitner, K. Clays, A. Persoons, C. Rovira, J. Veciana
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  ABSTRACT: Times Cited: 49
  43:5266-5268.
• Article: Racemic and enantiomerically pure phenyl alpha-nitronyl nitroxide radicals: influence of chirality on solution and solid state properties

  M. Minguet, D. B. Amabilino, J. Vidal-Gancedo, K. Wurst, J. Veciana
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  ABSTRACT: Times Cited: 13
  12:570-578.
• Article: Radical-ion salts based on C-60-TTF fused dyads

  J. Llacay, A. Perez-Benitez, M. Mas-Torrent, J. Vidal-Gancedo, J. Veciana, C. Rovira
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  ABSTRACT: Times Cited: 0
  102:1488-1489.
• Chapter: Stability of metallic state in new hydrated molecular metals: (BET-TTF)(2)X center dot 3H(2)O (X = Cl, Br)

  E. Laukhina, A. Perez-Benitez, M. Mas-Torrent, E. Ribera, J. Vidal-Gancedo, J. Veciana, C. Rovira, V. Laukhin
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  ABSTRACT: Times Cited: 0
  pages 277-284; , ISBN: 1-4020-0578-4
• Article: Stereochemistry and EPR investigation of a chiral molecular magnet

  J. Vidal-Gancedo, M. Minguet, D. Luneau, D. B. Amabilino, J. Veciana
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  ABSTRACT: Times Cited: 3
  65:723-726.
• Article: Synthesis and characterization of a nanoscopic molecular-scale wire bearing terminal redox-active polychlorotriphenylmethyl radicals

  O. Elsner, D. Ruiz-Molina, J. Vidal-Gancedo, C. Rovira, J. Veciana
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  ABSTRACT: Times Cited: 9
  1:117-120.
• Article: Synthesis, structural and magnetic properties of a series of copper(II) complexes containing a monocarboxylated perchlorotriphenylmethyl radical as a coordinating open-shell ligand

  D. Maspoch, D. Ruiz-Molina, K. Wurst, J. Vidal-Gancedo, C. Rovira, J. Veciana
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  ABSTRACT: Times Cited: 21
• Article: Influence of bridge topology and torsion on the intramolecular electron transfer

  V. Lloveras, J. Vidal-Gancedo, D. Ruiz-Molina, T. M. Figueira-Duarte, J. F. Nierengarten, J. Veciana, C. Rovira
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  ABSTRACT: Times Cited: 10
  131:291-305.
• Article: Persistent and transient open-shell species derived from C-60-TTF cyclohexene-fused dyads. (vol 38, pg 3909, 1997)

  J. Llacay, J. Veciana, J. Vidal-Gancedo, J. L. Bourdelande, R. Gonzalez-Moreno, C. Rovira
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  ABSTRACT: Times Cited: 0
  63:9144-9144.
• Article: Formation of a biradical species from a monoradical with a photo- and thermo isomerizable imine group

  D. Ruiz-Molina, I. Ratera, J. Vidal-Gancedo, N. Daro, J. F. Letard, C. Rovira, J. Veciana
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  ABSTRACT: Times Cited: 0
  121:1804-1805.
• Source

  Available from: Imma Ratera

  Article: Ferrocene triphenylmethyl radical donor-acceptor compounds. Towards the development of multifunctional molecular switches

  C. Sporer, I. Ratera, K. Wurst, J. Vidal-Gancedo, D. Ruiz-Molina, C. Rovira, J. Veciana
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  ABSTRACT: Times Cited: 2
• Article: Intramolecular electron transfer mediated by a tetrathiafulvalene (TTF) bridge

  P. Hudhomme, F. Dumur, N. Gautier, A. Gorgues, V. Lloveras, J. Vidal-Gancedo, J. Veciana, C. Rovira
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  ABSTRACT: Times Cited: 1
  114:509-510.