A crystallographic, EPR and theoretical study of the Jahn–Teller distortion in [CuTp2]				(Tp−				= tris{pyrazol-1-yl}hydridoborate)

Colin A. Kilner; Eric J. L. McInnes; Michael A. Leech; Godfrey S. Beddard; Judith A. K. Howard; Frank E. Mabbs; David Collison; Adam J. Bridgeman; Malcolm A. Halcrow

doi:10.1039/B312426F

A crystallographic, EPR and theoretical study of the Jahn–Teller distortion in [CuTp₂] (Tp⁻ = tris{pyrazol-1-yl}hydridoborate)

Colin A. Kilner,^a Eric J. L. McInnes,^b Michael A. Leech,^c Godfrey S. Beddard,^a Judith A. K. Howard,^c Frank E. Mabbs,^b David Collison,^b Adam J. Bridgeman^d and Malcolm A. Halcrow*^a

Author affiliations

* Corresponding authors

^a Department of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK
E-mail: M.A.Halcrow@chem.leeds.ac.uk

^b EPSRC CW EPR Service, Department of Chemistry, University of Manchester, Oxford Road, Manchester, UK

^c Department of Chemistry, University of Durham, South Road, Durham, UK

^d Department of Chemistry, University of Hull, Kingston Upon Hull, UK

Abstract

Crystals of the title compound (1) contain two independent, centrosymmetric half-molecules per asymmetric unit. While both of these show Jahn–Teller elongated six-coordinate geometries, the lengths of the elongated Cu–N bonds in the two molecules differ by 0.117(2) Å at 30 K. The structure of one of these molecules (molecule A) does not vary with temperature below 350 K. The other molecule (molecule B) shows Cu–N bond lengths that are temperature-dependent between 225 and 375 K, but do not vary further at lower temperature. This indicates a fluxional axis of Jahn–Teller elongation in this molecule at these higher temperatures. Consideration of the thermal parameters in these structures implies that the fluxionality in molecule B is frozen out near 150 K. This conclusion is supported by a Q-band powder EPR study. The d–d transition energies of molecules A and B have been calculated by several density function (DF) methods, including a time-dependent DF calculation. The crystallographic data have been reproduced using the vibronic coupling model of Bürgi and Hitchman. This has shown that the different fluxionality regimes for molecules A and B are not a consequence of their different static molecular structures, but rather reflect their different local environments in the crystal.

Article information

https://doi.org/10.1039/B312426F

Article type

Paper

Submitted

07 Oct 2003

Accepted

17 Nov 2003

First published

04 Dec 2003

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Dalton Trans., 2004, 236-243

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A crystallographic, EPR and theoretical study of the Jahn–Teller distortion in [CuTp₂] (Tp⁻ = tris{pyrazol-1-yl}hydridoborate)

C. A. Kilner, E. J. L. McInnes, M. A. Leech, G. S. Beddard, J. A. K. Howard, F. E. Mabbs, D. Collison, A. J. Bridgeman and M. A. Halcrow, Dalton Trans., 2004, 236 DOI: 10.1039/B312426F

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Dalton Transactions

A crystallographic, EPR and theoretical study of the Jahn–Teller distortion in [CuTp₂] (Tp⁻ = tris{pyrazol-1-yl}hydridoborate)

Abstract

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A crystallographic, EPR and theoretical study of the Jahn–Teller distortion in [CuTp₂] (Tp⁻ = tris{pyrazol-1-yl}hydridoborate)

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