UNIGE document Scientific Article
previous document  unige:3558  next document
add to browser collection
Title

Mono- and Bis(tetrathiafulvalene)-1,3,5-Triazines as Covalently Linked Donor-Acceptor Systems: Structural, Spectroscopic, and Theoretical Investigations

Authors
Riobé, François
Avarvari, Narcis
Published in Chemistry - A European Journal. 2009, vol. 15, no. 2, p. 380-387
Abstract Reaction of 2,4,6-trichloro-1,3,5-triazine with lithiated tetrathiafulvalene (TTF) in stoichiometric conditions, followed by treatment with sodium methanolate, provides mono- and bis(TTF)-triazines as new covalently linked (multi)donor-acceptor systems. Single-crystal X-ray analyses reveal planar structures for both compounds, with formation of peculiar segregated donor and acceptor stacks for the mono(TTF)-triazine compound, while mixed TTF-triazine stacks establish in the case of the bis(TTF) derivative. Cyclic voltammetry measurements show reversible oxidation of the TTF units, at rather low potential, with no splitting of the oxidation waves in the case of the dimeric TTF, whereas irreversible reduction of the triazine core is observed. Intramolecular charge transfer is experimentally evidenced through solution electronic absorption spectroscopy. Time-dependent DFT calculations allow the assignment of the charge transfer band to singlet transitions from the HOMO of the donor(s) to the LUMO of the acceptor. Solution EPR measurements correlated with theoretical calculations were performed in order to characterize the oxidized species. In both cases the spectra show very stable radical species and contain a triplet of doublet pattern, in agreement with the coupling of the unpaired electron with the three TTF protons. The dication of the bis(TTF)-triazine is paramagnetic, but no spin-spin exchange interaction could be detected.
Keywords Charge transferDonor-acceptor systemsEPR spectroscopyNitrogen heterocyclesStructure elucidationTetrathiafulvalenes
Identifiers
Full text
Structures
Research group Groupe Geoffroy
Citation
(ISO format)
RIOBÉ, François et al. Mono- and Bis(tetrathiafulvalene)-1,3,5-Triazines as Covalently Linked Donor-Acceptor Systems: Structural, Spectroscopic, and Theoretical Investigations. In: Chemistry - A European Journal, 2009, vol. 15, n° 2, p. 380-387. https://archive-ouverte.unige.ch/unige:3558

289 hits

264 downloads

Update

Deposited on : 2009-10-02

Export document
Format :
Citation style :