Spin Crossover in a Hexaamineiron(II) Complex: Experimental Confirmation of a Computational Prediction

Paul V. Bernhardt, Jessica K. Bilyj, Victor Brosius, Dmitry Chernyshov, Robert J. Deeth, Marco Foscato, Vidar R. Jensen, Nicole Mertes, Mark J. Riley, Karl W. Törnroos

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6 Citations (SciVal)


Single crystal structural analysis of [FeII(tame)2]Cl2MeOH (tame=1,1,1-tris(aminomethyl)ethane) as a function of temperature reveals a smooth crossover between a high temperature high-spin octahedral d6 state and a low temperature low-spin ground state without change of the symmetry of the crystal structure. The temperature at which the high and low spin states are present in equal proportions is T1/2=140K. Single crystal, variable-temperature optical spectroscopy of [FeII(tame)2]Cl2MeOH is consistent with this change in electronic ground state. These experimental results confirm the spin activity predicted for [FeII(tame)2]2+ during its de novo artificial evolution design as a spin-crossover complex [Chem. Inf. Model. 2015, 55, 1844], offering the first experimental validation of a functional transition-metal complex predicted by such in silico molecular design methods. Additional quantum chemical calculations offer, together with the crystal structure analysis, insight into the role of spin-passive structural components. A thermodynamic analysis based on an Ising-like mean field model (Slichter-Drickammer approximation) provides estimates of the enthalpy, entropy and cooperativity of the crossover between the high and low spin states.

Original languageEnglish
Pages (from-to)5082-5085
Number of pages4
JournalChemistry - A European Journal
Issue number20
Early online date29 Jan 2018
Publication statusPublished - 6 Apr 2018

Bibliographical note

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


  • amines
  • density functional calculations
  • iron
  • optical spectroscopy
  • spin crossover

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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