Electron spin resonance detection of Jahn-Teller effect induced phase transition with thermal hysteresis in the copper(II) doped zinc(II)-bis- histidine systems: Free and hindered rotation of histidine molecules in solid lattice

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Anomalous temperature effects of the ESR spectra were found in copper doped zinc (II)-bis-(histidine) powders. In the L-histidine complex, reversible transitions between solid-like and liquid-like spectra were observed at 8 °C by increasing, and at 0 ́C by decreasing temperature. In the mixed L-histidine-D-histidine complex, the magnetic parameters of solid-like spectra change strongly around -20°C. The anomalies were explained by Jahn-Teller effect stabilized square planar geometry around the doping copper centers in the lattice of zinc complex with tetrahedral geometry. The phase transitions can be induced by rearrangements of the water molecules coordinated to the copper ions into their regular positions in the zinc lattice. This molecular displacement can facilitate either uniaxial rotation or torsional oscillation of the histidine molecules in the respective lattices.

Original languageEnglish
Pages (from-to)976-979
Number of pages4
JournalThe Journal of Chemical Physics
Issue number2
Publication statusPublished - Dec 1 1986


ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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