Solution electrochemistry of indolenium squarylium cyanine dyes
Faculty of Sciences. Chemistry
Engineering sciences. Technology
Dyes and pigments. - London
, p. 113-116
University of Antwerp
The redox potential of a class of donor-acceptor-donor (D-A-D) molecules, bis(5-substituent-2,3,3,-trimethyl-indolenium-2-ylidene)squaraines (Sq 1-8), were determined. All the dyes exhibit two reversible oxidation potentials in methanol. C-5 substituents at the indolenium moieties exert a small effect on the first oxidation potential, and the substituent effect is attributed to the inductive parameters. The frontier orbital energy levels were calculated by the AM1-SCF method. A good linear relationship between the highest occupied molecular orbital energy level and the first oxidation potential was found. (C) 1999 Elsevier Science Ltd. All rights reserved.