Hyperfine Interactions

, Volume 93, Issue 1, pp 1597–1603 | Cite as

Systematic search for spontaneous neutral to ionic and ionic to neutral transitions in organometallic materials based on minimally alkylated ferrocenes and classical polycyanide electron acceptors

  • A. Quazi
  • W. M. Reiff
  • R. U. Kirss
Phase Transitions, Relaxsation, and Valence Fluctuations

Abstract

Methyl-, ethyl- and n-butyl ferrocene (I–III) form dark colored charge transfer complexes with TCNE both in solution and by trituration of the solid donor and acceptor. Their Mössbauer spectra suggest only minor reduction of the TCNE acceptor. On the other hand, 1,1′-dimethylferrocene (IV) forms a ferricenium complex with TCNE of 1∶2 stoichiometry whose structure is likely similar to that determined for [IV][TCNQ]2. The new 1∶2 ferricenium-TCNE phase undergoes a novel, spontaneous, irreversible solid-state transformation back to a mixture of a low spin FeII ferrocene species and a high spin FeII complex over a period of weeks at ambient temperature. In preliminary studies, irradiation of samples of these materials with white light (including near infrared wavelengths) suggests significant photochemical activity of the type\(D^0 A^0 \xrightarrow{{hv}}D^ + A^ - \) and vice versa in the solid state. This is observable in Mössbauer spectra at 77 K. In the absence of irradiation with tungsten-halogen white light sources, however, the photo product is not permanently trapped at this temperature.

Keywords

High Spin Ferrocene Charge Transfer Complex TCNQ Photochemical Activity 

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Copyright information

© J.C. Baltzer AG, Science Publishers 1994

Authors and Affiliations

  • A. Quazi
    • 1
  • W. M. Reiff
    • 1
  • R. U. Kirss
    • 1
  1. 1.Department of ChemistryNortheastern UniversityBostonUSA

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