Journal
TETRAHEDRON
Volume 56, Issue 25, Pages 4203-4211Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0040-4020(00)00345-8
Keywords
violenes; cyanines; redox chemistry; electrochromics; heterocycles
Categories
Ask authors/readers for more resources
Synthesis, cyclic voltammetry (CV) and spectroelectrochemistry (SE) of tetra-onium salts 3(OX)(+4).4BF(4)(-) and 6(OX)(+4).4PF(6)(-) are presented for both systems. Cyclic voltammograms display several reduction and oxidation peaks containing at least one reversible pair. The colorless tetracations on reduction reversibly develop long wavelength absorptions. Absorption bands arise which are attributed to 3(RED)(+2) and 6(RED/OX)(+2), respectively. The latter is further reversibly reduced to colorless 6(RED)(0) for which a cyclic structure with a central four-membered ring is proposed. Radical ions like 3 (6)(SEM)(.+3) and 3 (6)(SEM)(.+1) were not detected by CV or SE. PM3 calculations of 6(OX)(+4) down to 6(RED)(0) change and verify two perpendicular cyanine units in 6(RED/OX)(+2) as well as the cyclic structure for 6(RED)(0), which is of 29.86 kcal/mol more stable than the corresponding acyclic one. Systems 7-12 described in the literature are discussed as vinylogous examples of A which also displayreversible two electron transfer with strong changes in color. (C) 2000 Elsevier Science Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available