University Of Tasmania
Browse

File(s) not publicly available

Cooperative Jahn-Teller Interactions in dynamic copper(II) complexes. Temperature dependence of the crystal structure and EPR spectrum of deuterated ammonium copper(II) sulfate hexahydrate

journal contribution
posted on 2023-05-16, 11:44 authored by Hitchman, MA, Maaskant, W, van der Plas, J, Simmons, CJ, Stratemeier, H
The crystal structure of the deuterated Tutton salt (ND 4) 2[Cu(D 2O) 6](SO 4) 2 determined by X-ray diffraction at several temperatures between 100 and 321 K is reported. The intermediate and longest Cu-O bond lengths of the Jahn-Teller distorted octahedral Cu(D 2O) 6 2+ ion progressively converge as the temperature is raised above ~200 K, and this is accompanied by a partial rotation of the ammonium and sulfate groups. The g-values derived from the EPR spectrum of the compound exhibit similar behavior, as do those of ~1% Cu 2+ doped into the isomorphous zinc(II) compound. The temperature dependence of the g-values of Cu 2+doped (ND 4) 2[Zn(D 2O) 6](SO 4) 2 may be interpreted satisfactorily by a model which assumes a Boltzmann thermal distribution between two energy states which differ solely in the orientation of the Cu(D 2O) 6 2+ ion in the lattice. However, such a model does not Satisfactorily explain the behavior of pure (ND 4) 2[Cu(D 2O) 6](SO 4) 2, and it is suggested that this is due to cooperative interactions. A new model, in which the probable energy state of each complex is estimated after taking into account the likely orientations of its neighbors in the lattice, is described. Application of this model suggests that the thermal behavior is dominated by the cooperative interactions between complexes, these being transmitted via the hydrogen- bonding network. Comparisons are drawn with the cooperative interactions observed in more strongly coupled Jahn-Teller systems and in compounds for which the structural changes are associated with equilibria between two spin states.

History

Publication title

Journal of the American Chemical Society

Volume

121

Issue

7

Pagination

1488-1501

ISSN

0002-7863

Department/School

School of Natural Sciences

Publisher

American Chemical Society

Place of publication

USA

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the chemical sciences

Usage metrics

    University Of Tasmania

    Exports