Photochemistry of thioxanthones VI: A polymerization, spectroscopic and flash photolysis study on novel water-soluble substituted 3-(9-oxo-9H-thioxanthene-2,3-γ-4-yloxy)-N,N,N-trimethyl-1-propanaminium salts

摘要: Abstract The photopolymerization activity and photochemistry of nine novel water-soluble 3-(9-oxo-9H-thioxanthene-2,3-γ-4-yloxy)-N,N,N-trimethyl-1-propanaminium salts is examined in water 2-propanol using absorption, luminescence conventional microsecond flash photolysis techniques. For both the chloro methylsulphonate salts, follows order substitution 4- > 2- 3-. Methyl 1-position deactivates molecule this reflected by a reduction (fluorescence phosphorescence) quantum yields triplet lifetime. Intramolecular hydrogen-atom abstraction main competitive process suppressing photochemical activity. longest wavelength absorption maxima extinction coefficients are similar to those 2-substituted derivatives studied previously, indicating lowest excited singlet state with strong nn* character. On changing solvent from all fluorescence enhanced consistent degree charge transfer character state. From results, transient absorptions below 400 nm associated intermediate ketyl radical formed singlet/triplet states thioxanthene abstracting hydrogen atom amine synergist (used photopolymerization) while above anion concurrent electron amine. latter confirmed through detailed study on effect pH concentration production, as well various amines increasing ionization potential. Transient formation only partly reduced aerobic conditions our earlier findings conclusions that associated, main, thioxanthone tertiary synergist. This correlation between potential different amines.