Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Per Persson. Photo.

Per Persson

Director

Per Persson. Photo.

Structure of Jahn-Teller distorted solvated copper(II) ions in solution, and in solids with apparently regular octahedral coordination geometry

Author

  • I. Persson
  • Per Persson
  • M. Sandstrom
  • A. S. Ullstrom

Summary, in English

Regular octahedral coordination has been reported for some copper(II) complexes in the solid state on the basis of crystallographic studies, e.g. hexaaquacopper(II) bromate, [Cu(OH2)(6)](BrO3)(2). hexaaquacopper(II) hexafluorosilicate, [Cu(OH2)(6)]Si-6, and hexakis(pyridine-1-oxide)copper(II) perchlorate. [Cu(ONC5H5)(6)](ClO4)(2). These results are not consistent with the elongated octahedral configuration expected from the Jahn-Teller theorem for the d(9) copper(II) ion nor, in some cases, with results from electron spin resonance studies. The present lattice-independent EXAFS study confirms that the local structure in the copper(II) complexes mentioned above is, in all cases, consistent with a Jahn-Teller induced elongation. Mean equatorial and axial Cu-O bond distances of 1.96(1) and 2.32(2) Angstrom, and 1.95(1) and 2.27(3) Angstrom, were obtained for the hexaaquacopper(II) ions in the bromate and hexafluorosilicate salts, respectively, For the hexakis(pyridine-1-oxide)copper(II) perchlorate only the equatorial mean Cu 0 bond distance of 1.96(1) Angstrom could be observed. Evidently, there is orientational disorder of the tetragonally elongated octahedral complexes resulting in too high crystallographic space group symmetry and copper sites in apparently regular coordination geometry. For the hydrated copper(II) ion in aqueous solution, five- and six-coordinated models with different geometries have been evaluated by means of EXAFS and large angle X-ray diffraction (LAXS) data. The combined results are consistent with a Jahn-Teller elongated octahedral configuration with Cu-O-eq 1.95(1) Angstrom, Cu-O-ax 2.29(3) Angstrom, and a distinct second hydration sphere with about eight water molecules and a mean Cu...O-II distance of 4.17(3) Angstrom. In dimethylsulfoxide solution EXAFS and LAXS methods show the solvated copper(II) ions to have mean equatorial and axial Cu-O bond distances of 1.96(1) and 2.24(2) Angstrom, respectively, As a model compound for the EXAFS studies, the crystal structure of hexakis(dimethylsulfoxide)copper(II) perchlorate dimethylsulfoxide (1/2), [Cu(OS(CH3)(2))(6)](ClO4)(2).2(CH3)(2)SO, was determined.

Publishing year

2002

Language

English

Pages

1256-1265

Publication/Series

Journal of the Chemical Society. Dalton Transactions

Issue

7

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Earth and Related Environmental Sciences

Status

Published

ISBN/ISSN/Other

  • ISSN: 1472-7773