Engineering a remarkably low HOMO-LUMO gap by covalent linkage of a strong π-donor and a π-acceptor-tetrathiafulvalene-σ-polynitrofluorene diads: Their amphoteric redox behavior, electron transfer and spectroscopic properties

Perepichka, D.F.; Bryce, M.R.; Batsanov, A.S.; McInnes, E.J.L.; Zhao, J.P.; Farley, R.D.

Abstract

Novel R3TTF-sigma-A compounds 14, 16 and 19 (R3TTF = trial-kyltetrathiafulvalene, sigma = saturated spacer, A = polynitrofluoren-9-dicyano-methylene acceptor) incorporating very strong donor and acceptor moieties have been synthesized by condensation of the corresponding R3TTF-sigma-fluoren-9-one diads with malononitrile. Reversible five-step amphoteric redox behavior has been observed with an extremely low HOMO-LUMO gap (approximate to 0.3 eV). For compound 14 a strong EPR signal is observed in the solid state, ascribed to intermolecular complexation: a less intense signal is seen in solution, corresponding to ca. 2% of the molecules existing in a radical form at room temperature. Intramolecular charge transfer in diads 14 and 16 is manifested in strong absorption bands in the near-IR region of their electronic spectra. Spectroelectrochemical data reveal marked electrochromic behavior in the visible and near-IR region of both compounds. The first X-ray crystal structure of a fluorene radical-anion salt is reported, namely the copper salt of 2,4,5,7-tetranitro-9-dicyanomethylenefluorene (1:1 stoichiometry).

Citation

Perepichka, D., Bryce, M., Batsanov, A., McInnes, E., Zhao, J., & Farley, R. (2002). Engineering a remarkably low HOMO-LUMO gap by covalent linkage of a strong π-donor and a π-acceptor-tetrathiafulvalene-σ-polynitrofluorene diads: Their amphoteric redox behavior, electron transfer and spectroscopic properties. Chemistry - A European Journal, 8(20), 4656-4669. https://doi.org/10.1002/1521-3765%2820021018%298%3A20%3C4656%3A%3Aaid-chem4656%3E3.0.co%3B2-1

• Journal Article Type: Article
• Publication Date: Oct 18, 2002
• Deposit Date: Apr 26, 2007
• Journal: Chemistry - A European Journal
• Print ISSN: 0947-6539
• Electronic ISSN: 1521-3765
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 20
• Pages: 4656-4669
• DOI: https://doi.org/10.1002/1521-3765%2820021018%298%3A20%3C4656%3A%3Aaid-chem4656%3E3.0.co%3B2-1
• Public URL: https://durham-repository.worktribe.com/output/1592991