Ivan Nemec

2011

• I. Nemec, R. Herchel, R. Boca, I. Svoboda, Z. Travnicek, L. Dlhan, K. Matelkova, and H. Fuess, “Heterobimetallic assemblies of Ni(II) complexes with a tetradentate
  amine ligand and diamagnetic cyanidometallates,” INORGANICA CHIMICA ACTA, vol. 366, iss. 1, pp. 366-372, 2011.
  [Bibtex]

  @article ISI:000285994200049,
  Author = Nemec, Ivan and Herchel, Radovan and Boca, Roman and Svoboda, Ingrid and
     Travnicek, Zdenek and Dlhan, Lubor and Matelkova, Kristina and Fuess,
     Hartmut,
  Title = Heterobimetallic assemblies of Ni(II) complexes with a tetradentate
     amine ligand and diamagnetic cyanidometallates,
  Journal = INORGANICA CHIMICA ACTA,
  Year = 2011,
  Volume = 366,
  Number = 1,
  Pages = 366-372,
  Month = JAN 30,
  Abstract = Syntheses and crystal structures of nickel(II) complexes containing teta
     (teta = N,N'-bis(2-aminoethyl)ethane-1,2-diamine) as a tetradentate
     blocking ligand and cyanidometallic bridging complexes are described.
     The complexes [Ni(teta)(cis-mu(2)-Ni(CN)(4))] (1) and
     [\Ni(teta)\(3)(mu(6)-Co(CN)(6))] (ClO(4))(3) (2) exhibit a
     1D-polymeric structure whereas the heterometallic trinuclear complex
     [Ni(teta)(mu(1)-Ag(CN)(2))(2)] (3) forms a unique network. The weak
     antiferromagnetic exchange was found in polymeric species 1 and 2 by
     analyzing the magnetic data with several models in which either only
     susceptibility was treated or simultaneous fitting of temperature and
     magnetic field dependences of the magnetization was applied using the
     finite-size closed ring approach. Moreover, an effect of the zero-field
     splitting phenomenon (ZFS) was considered for 2 by advanced modeling of
     magnetic properties for varying axial ZFS parameter/isotropic exchange
     (D/J) ratios. (C) 2010 Elsevier B.V. All rights reserved.,
  DOI = 10.1016/j.ica.2010.11.028,
  ISSN = 0020-1693,
  Unique-ID = ISI:000285994200049,
  

• I. Nemec, R. Herchel, R. Boca, Z. Travnicek, I. Svoboda, H. Fuess, and W. Linert, “Tuning of spin crossover behaviour in iron(III) complexes involving
  pentadentate Schiff bases and pseudohalides,” DALTON TRANSACTIONS, vol. 40, iss. 39, pp. 10090-10099, 2011.
  [Bibtex]

  @article ISI:000295843100018,
  Author = Nemec, Ivan and Herchel, Radovan and Boca, Roman and Travnicek, Zdenek
     and Svoboda, Ingrid and Fuess, Hartmut and Linert, Wolfgang,
  Title = Tuning of spin crossover behaviour in iron(III) complexes involving
     pentadentate Schiff bases and pseudohalides,
  Journal = DALTON TRANSACTIONS,
  Year = 2011,
  Volume = 40,
  Number = 39,
  Pages = 10090-10099,
  Abstract = Investigations on a series of eight novel mononuclear iron(III) Schiff
     base complexes with the general formula [Fe(L(5))(L(1))]center dot S
     (where H(2)L(5) = pentadentate Schiff-base ligand, L(1) = a pseudohalido
     ligand, and S is a solvent molecule) are reported. Several different
     aromatic 2-hydroxyaldehyde derivatives were used in combination with a
     non-symmetrical triamine 1,6-diamino-4-azahexane to synthesize the
     H(2)L(5) Schiff base ligands. The consecutive reaction with iron(III)
     chloride resulted in the preparation of the [Fe(L(5))Cl] precursor
     complexes which were left to react with a wide range of the L(1)
     pseudohalido ligands. The low-spin compounds were prepared using the
     cyanido ligand: [Fe(3m-salpet)(CN)]center dot CH(3)OH (1a),
     [Fe(3e-salpet)(CN)]center dot H(2)O (1b), while the high-spin
     compounds were obtained by the reaction of the pseudohalido (other than
     cyanido) ligands with the [Fe(L(5))Cl] complex arising from
     salicylaldehyde derivatives: [Fe(3Bu5Me-salpet)(NCS)] (2a),
     [Fe(3m-salpet)(NCO)]center dot CH(3)OH (2b) and
     [Fe(3m-salpet)-(N(3))] (2c). The compounds exhibiting spin-crossover
     phenomena were prepared only when L(5) arose from
     2-hydroxy-1-naphthaldehyde (H(2)L(5) = H(2)napet):
     [Fe(napet)(NCS)]center dot CH(3)CN (3a, T(1/2) = 151 K),
     [Fe(napet)(NCSe)]center dot CH(3)CN (3b, T(1/2) = 170 K),
     [Fe(napet)(NCO)] (3c, T(1/2) = 155 K) and [Fe(napet)(N(3))], which,
     moreover, exhibits thermal hysteresis (3d, T(1/2)up arrow = 122 K,
     T(1/2)down arrow = 117 K). These compounds are the first examples of
     octahedral iron(III) spin-crossover compounds with the coordinated
     pseudohalides. We report the structure and magnetic properties of these
     complexes. The magnetic data of all the compounds were analysed using
     the spin Hamiltonian formalism including the ZFS term and in the case of
     spin-crossover, the Ising-like model was also applied.,
  DOI = 10.1039/c1dt10696a,
  ISSN = 1477-9226,
  Unique-ID = ISI:000295843100018,
  

2009

• I. Nemec, R. Boca, M. Gembicky, L. Dlhan, R. Herchel, and F. Renz, “High-spin Schiff-base dinuclear iron(III) complexes bridged by N-oxide
  ligands,” INORGANICA CHIMICA ACTA, vol. 362, iss. 13, pp. 4754-4759, 2009.
  [Bibtex]

  @article ISI:000270168500015,
  Author = Nemec, Ivan and Boca, Roman and Gembicky, Milan and Dlhan, Lubor and
     Herchel, Radovan and Renz, Franz,
  Title = High-spin Schiff-base dinuclear iron(III) complexes bridged by N-oxide
     ligands,
  Journal = INORGANICA CHIMICA ACTA,
  Year = 2009,
  Volume = 362,
  Number = 13,
  Pages = 4754-4759,
  Month = OCT 15,
  Abstract = Synthesis and structure of dinuclear complexes
     [\Fe(III)(L(5))\b\Fe(III)(L(5))\](BPh(4))(2), where L(5) is a
     pentadentate Schiff-base ligand, b is a bidentate N-oxide bridging
     ligand based on bipyridine, is reported. Magnetic behavior is
     investigated in terms of the magnetic susceptibility, magnetization, and
     Mossbauer spectroscopy revealing that the complexes are high-spin over
     the whole temperature region. (C) 2009 Elsevier B. V. All rights
     reserved.,
  DOI = 10.1016/j.ica.2009.06.057,
  ISSN = 0020-1693,
  Unique-ID = ISI:000270168500015,
  

• R. Boca, I. Nemec, I. Salitros, J. Pavlik, R. Herchel, and F. Renz, “Interplay between spin crossover and exchange interaction in iron(III)
  complexes,” PURE AND APPLIED CHEMISTRY, vol. 81, iss. 8, pp. 1357-1383, 2009.
  [Bibtex]

  @article ISI:000269408000002,
  Author = Boca, Roman and Nemec, Ivan and Salitros, Ivan and Pavlik, Jan and
     Herchel, Radovan and Renz, Franz,
  Title = Interplay between spin crossover and exchange interaction in iron(III)
     complexes,
  Journal = PURE AND APPLIED CHEMISTRY,
  Year = 2009,
  Volume = 81,
  Number = 8,
  Pages = 1357-1383,
  Month = AUG,
  Abstract = In the dinuclear and polynuclear metal complexes exhibiting the low-spin
     (LS) to high-spin (HS) transition, the spin-crossover phenomenon
     interferes with the magnetic exchange interaction. The latter manifests
     itself in forming spin-multiplets, which causes a possible overlap of
     the band originating in different reference spin states (ILL, LH, HL,
     and HH). A series of dinuclear Fe(III) complexes has been prepared; the
     iron centers are linked by a bidentate bridge (CN(-), and diamagnetic
     metallacyanates \Fe(CN)(5)(NO)\, \Ni(CN)(4)\ \Pt(CN)(4)\, and
     \Ag(CN)(2)\). Magnetic measurements confirm that the spin crossover
     proceeds on the thermal propagation. This information has been completed
     also by the Mossbauer spectral (MS) data. A theoretical model has been
     developed that allows a simultaneous fitting of all available
     experimental data (magnetic susceptibility, magnetization, HS mole
     fraction) on a common set of parameters.,
  DOI = 10.1351/PAC-CON-08-07-20,
  ISSN = 0033-4545,
  Unique-ID = ISI:000269408000002,
  

• I. Nemec, R. Boca, R. Herchel, Z. Travnicek, M. Gembicky, and W. Linert, “Dinuclear Fe(III) complexes with spin crossover,” MONATSHEFTE FUR CHEMIE, vol. 140, iss. 7, pp. 815-828, 2009.
  [Bibtex]

  @article ISI:000266926500011,
  Author = Nemec, Ivan and Boca, Roman and Herchel, Radovan and Travnicek, Zdenek
     and Gembicky, Milan and Linert, Wolfgang,
  Title = Dinuclear Fe(III) complexes with spin crossover,
  Journal = MONATSHEFTE FUR CHEMIE,
  Year = 2009,
  Volume = 140,
  Number = 7,
  Pages = 815-828,
  Month = JUL,
  Abstract = A series of dinuclear Fe(III) complexes was synthesized in which the
     Schiff-base blocking ligand L(5) coordinates each of the centers which
     are linked by a bidentate, bipyridine-type ligand. For these systems,
     [L(5)Fe(III)\bridge\ Fe(III)L(5)](BPh(4))(2), thermally induced spin
     crossover is observed. The corollary of the systems is that the spin
     crossover interferes with the magnetic exchange interaction. The overlap
     of the energy bands of the LL and HH reference states (L, low-spin; H,
     high-spin) causes the exchange interaction to act against the spin
     crossover (leading to incompleteness or gradual behavior).,
  DOI = 10.1007/s00706-008-0096-0,
  ISSN = 0026-9247,
  Unique-ID = ISI:000266926500011,