Characterization of the Dielectric Properties of Polar Metal-Organic Frameworks Containing “Gyroscopic” Ligands

ORAL

Abstract

The metal-organic framework (MOF) Zn-F2BODCA-dabco occupies a tetragonal space group and is comprised of polar ligands in the ab plane, and interplanar non-polar ligands. Each ligand, or “rotor,” behaves as a molecular analogue to a gyroscope with a rotation axis in the intraplanar bond directions. Dielectric spectroscopy measurements on powder samples indicate an order-disorder phase transition involving the electric dipoles at 100K, followed by a Debye-like crossover at lower temperature. Analyzing the data as a ferroelectric transition close to 100K reveals a dipole moment on the order of the nominal dipole value of 2 Debye. Nuclear Magnetic Resonance (NMR) measurements suggests an Arrhenius freeze-out of rotational motion of the non-polar interplanar ligands, occurring within a small temperature range of the Debye-like crossover, suggestive of a correlation between the two dynamical effects. We present these results, as well as modeling with Monte Carlo simulations.

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Presenters

  • Erik Lamb

    Physics and Astronomy, University of California, Los Angeles, Higher Education Research Experience, Oak Ridge Institute for Science and Education

Authors

  • Erik Lamb

    Physics and Astronomy, University of California, Los Angeles, Higher Education Research Experience, Oak Ridge Institute for Science and Education

  • Salvador Perez-Estrada

    Chemistry and Biochemistry, University of California, Los Angeles

  • Yue-Shun Su

    Department of Physics and Astronomy, UCLA, Physics and Astronomy, University of California, Los Angeles

  • Tim Chung

    Chemistry and Biochemistry, University of California, Los Angeles

  • Trevor Chang

    Chemistry and Biochemistry, University of California, Los Angeles

  • Miguel Garcia-Garibay

    Chemistry and Biochemistry, University of California, Los Angeles

  • Stuart Brown

    Department of Physics and Astronomy, UCLA, Physics and Astronomy, Univ of California - Los Angeles, Physics and Astronomy, University of California, Los Angeles, Department of Physics & Astronomy, Univ of California - Los Angeles, Physics and Astronomy, UCLA