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Probing the unpaired Fe spins across the spin crossover of [Fe(L1)(bipy)]<sub>n</sub> coordination polymer by X-ray photoemission spectroscopy

ORAL

Abstract

The spin crossover (SCO) phenomenon occurs in 3d transition metal compounds and is typically a temperature-induced transition of diamagnetic low spin (LS) state to paramagnetic high spin (HS) state. Intermolecular cooperative effects can be seen in the spin crossover transition which results a thermal hysteresis. The steric hindrance can result in thermal stabilization and can affect the spin transition temperature. This can also result in a mixed spin state for a given temperature. This bistability of these SCO molecules is important in implementing a spin crossover complex into a molecular device. In this study the spin-crossover coordination polymer [Fe(L1)(bipy)]n (where L is a N2O22− coordinating Schiff base-like ligand bearing a phenazine fluorophore and bipy = 4,4′-bipyridine), which exhibits a wide thermal hysteresis, above room temperature has been studied using different methods. The spin state transition temperatures obtained from XAS and XPS differ from temperature determined from magnetometry. This suggests that XAS and XPS may perturb the bistability of the spin crossover system or that the surface of a [Fe(L1)(bipy)]n crystal differs from the bulk.

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Presenters

  • Thilini Ekanayaka

    Department of Physics and Astronomy, University of Nebraska - Lincoln

Authors

  • Thilini Ekanayaka

    Department of Physics and Astronomy, University of Nebraska - Lincoln

  • Hannah Kurz

    Inorganic Chemistry IV, University of Bayreuth.

  • Ashley S. Dale

    Department of Physics, Indiana University Purdue University-Indianapolis

  • Guanhua Hao

    Department of Physics and Astronomy, University of Nebraska - Lincoln

  • Aaron Mosey

    Department of Physics, Indiana University Purdue University-Indianapolis

  • Esha Mishra

    Department of Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska-Lincoln

  • Alpha N'Diaye

    Advanced Light Source, Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory, Lawrence Berkeley Laboratory, E O Lawrence Berkeley National Laboratory, Berkeley, CA, US, academic/govt, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Ruihua Cheng

    Department of Physics, Indiana University Purdue University-Indianapolis

  • Birgit Weber

    Inorganic Chemistry IV, University of Bayreuth.

  • Peter A Dowben

    Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska-Lincoln, University of Nebraska - Lincoln