Mononuclear Complexes of Iron(II) Based on Symmetrical Tripodand Ligands: Novel Parent Systems for the Development of New Spin Crossover Metallomesogens

Authors

  • Maksym Seredyuk,

    1. Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger-Weg 9, 55099 Mainz, Germany
    2. National Taras Shevchenko University, Department of Physical Chemistry, Volodymyrska Str. 64, Kiev 01601, Ukraine
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  • Ana B. Gaspar,

    1. Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger-Weg 9, 55099 Mainz, Germany
    2. Institut de Ciència Molecular (ICMOL), Departament de Química Inorgànica, Universitat de València, Edifici de Instituts de Paterna, Apartat de Correus 22085, 46071 Valencia, Spain
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  • Joachim Kusz,

    1. Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger-Weg 9, 55099 Mainz, Germany
    2. Institute of Physics, University of Silesia, 4 Uniwersytecka Str., 40007 Katowice, Poland
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  • Prof. Dr. Philipp Gütlich

    Corresponding author
    1. Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger-Weg 9, 55099 Mainz, Germany
    • Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger-Weg 9, 55099 Mainz, Germany
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  • In Memory of Professor Hans Georg von Schnering

  • Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/zaac.201100034 or from the author.

Abstract

The synthesis and characterization of a series of mononuclear tripodand-based FeII complexes by means of Mössbauer andUV/Vis spectroscopic as well as magnetic methods is reported. The complexes were obtained from the reactions of FeII salt with heterocyclic aldehydes (imd = imidazole-4(5)-carboxaldehyde, py = picolinaldehyde, or 6-Mepy = 6-methylpicolinaldehyde) and a symmetric triamine [tren = tris(2-aminoethyl)amine, tame = 2,2,2-tris(aminomethyl)ethane, or tach = 1,3,5-cis,cis-cyclohexanetriamin]. Because of extreme rigidity of the capping triamine tach, the molecular structure of {Fe[tach(imd)3](BF4)2} (1) features an unprecedented tapered trigonal prismatic FeN6 polyhedron. The molecular structures of the complexes {Fe[tach(py)3](ClO4)2} (2), {Fe[tame(imd)3](ClO4)2} (3), {Fe[tame(py)3](ClO4)2} (4) and {Fe[tame(6-Mepy)3](ClO4)2} (5) are quite similar and exhibit pseudo-octahedral arrangements of the coordination polyhedron. Compound 1 is in the high spin state, whereas compounds 25 are in the low spin state at all investigated temperatures (10–400 K). Chemical modification of the ligands in 25 to introduce liquid crystalline properties is expected to decrease the ligand field strength sufficiently to transform the electronic LS ground state to spin crossover behavior in the room temperature region.

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