R. Sarpal, M. Belletěte, G. Durocher
Oct 1, 1993
Citations
0
Influential Citations
14
Citations
Journal
Canadian Journal of Chemistry
Abstract
Five substituted derivatives of the main chromophore, 2-phenyl-3,3-dimethyl-3H-indole (1), have been studied over a wide range of acidity by UV absorption and steady state fluorescence spectroscopy. These are as follows: 2-[(p-amino)phenyl]-3,3-dimethyl-3H-indole (2), 2-[(p-dimethylamino)phenyl]-3,3-dimethyl-3H-indole (3), 2-[(p-amino)-phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (4), 2-[(p-methylamino)phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (5), and 2-[(p-dimethylamino)phenyl]-3,3-dimethyl-5-carboethoxy-3H-indole (6). The dependence of absorption and fluorescence spectral characteristics upon acidity has allowed us to characterize four species, namely, the anion (A), the neutral molecule (N), the cation (C), and the dication (DC), for molecules 2 and 3. Molecules 4, 5, and 6 give rise to an additional anion due to the hydrolysis of the ester group. The relative order of protonations to available sites is discussed. The ring-protonated species have shown the Phc and indole rings to be coplanar in bot...