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Angew Chem Int Ed Engl ; 54(19): 5583-7, 2015 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-25784624


The tape-like chain {[(tptz)Mn(II) (H2 O)Mn(III) (CN)6 ]2 Mn(II) (H2 O)2 }n ⋅4n MeOH⋅2n H2 O based on the anisotropic building block hexacyanomanganate(III) exhibits long-range magnetic ordering below 5.1 K as well as single-chain magnetic behavior at lower temperatures with an effective energy barrier of 40.5(7) K.

Dalton Trans ; 42(41): 14685-8, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24026666


The mononuclear ferric compound Fe(H-5-Cl-thsa-Me)(5-Cl-thsa-Me)·H2O () was synthesized and characterized using powder/single-crystal X-ray diffraction, Mössbauer spectroscopy, differential scanning calorimetry (DSC), and magnetic susceptibility measurements. This photo-responsive compound shows reversible, two-step spin-crossover behaviour. Moreover, dielectric anomalies were observed during the spin transitions, demonstrating the multifunctional properties of compound .

J Am Chem Soc ; 130(44): 14729-38, 2008 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-18839950


In this article we report for the first time experimental details concerning the synthesis and full characterization (including the single-crystal X-ray structure) of the spin-canted zigzag-chain compound [Co(H2L)(H2O)]infinity [L = 4-Me-C6H4-CH2N(CPO3H2)2], which contains antiferromagnetically coupled, highly magnetically anisotropic Co(II) ions with unquenched orbital angular momenta, and we also propose a new model to explain the single-chain magnet behavior of this compound. The model takes into account (1) the tetragonal crystal field and the spin-orbit interaction acting on each Co(II) ion, (2) the antiferromagnetic Heisenberg exchange between neighboring Co(II) ions, and (3) the tilting of the tetragonal axes of the neighboring Co units in the zigzag structure. We show that the tilting of the anisotropy axes gives rise to spin canting and consequently to a nonvanishing magnetization for the compound. In the case of a strong tetragonal field that stabilizes the orbital doublet of Co(II), the effective pseudo-spin-1/2 Hamiltonian describing the interaction between the Co ions in their ground Kramers doublet states is shown to be of the Ising type. An analytical expression for the static magnetic susceptibility of the infinite spin-canted chain is obtained. The model provides an excellent fit to the experimental data on both the static and dynamic magnetic properties of the chain.

J Phys Chem A ; 110(51): 14003-12, 2006 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-17181362


The paper is aimed at the elucidation of the main factors responsible for the single-chain magnet behavior of the cobalt(II) disphosphonate compound Co(H2L)(H2O) with a 1D structure. The model takes into account the spin-orbit interaction, the axial component of the octahedral crystal field acting on the ground-state cubic 4T1 terms of the Co(II) ions, the antiferromagnetic exchange interaction between Co(II) ions as well as the difference in the crystallographic positions of these ions. The conditions that favor the single-chain magnet behavior based on spin canting in a 1D chain containing inequivalent Co(II) centers are discussed. The peculiarities of this behavior in chains containing orbitally degenerate ions are revealed. The qualitative explanation of the experimental data is given.