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EPR of Two Cu2+ Complexes Showing Dynamic Jahn-Teller Effects
journal contribution
posted on 2023-05-16, 12:10 authored by Hitchman, MA, Simmons, CJ, Stratemeier, HThe powder electron paramagnetic resonance spectra of ̃1% Cu doped into [Zn(bipy)2(NO2)]NO3 and [Zn(bipyam)2(NO2)]NO3, bipy = 2,2′-bipyridyl, bipyam = 2,2′-bipyridylamine, over the temperature range 4.2-300 K are reported. For [Zn/Cu(bipy)2(NO2)]NO3 a spectrum characteristic of a tetragonally elongated octahedral complex with a slight orthorhombic distortion is observed below ̃50 K, but above this temperature the signals associated with the two higher g-values gradually converge. At low temperature a spectrum similar to that of the bipy complex is observed for [Zn/Cu(bipyam)2(NO2)]NO3, but between 40 and 60 K the spectrum gradually changes to one characteristic of a tetragonal g-tensor with g∥ < g⊥. The spectra may be interpreted satisfactorily with a model in which the temperature dependence of the g-values is estimated from the vibronic wavefunctions of a copper(II) complex under the influence of second-order Jahn-Teller coupling and a ligand field of tetragonal symmetry perturbed by crystal lattice forces. The results are consistent with the crystal structures reported for the compounds at various temperatures. © Springer-Verlag 2000.
History
Publication title
Applied Magnetic ResonanceVolume
19Pagination
121-131ISSN
0937-9347Department/School
School of Natural SciencesPublisher
Springer-VerlagPlace of publication
AustriaRepository Status
- Restricted