Photochemistry of thioxanthones—V. A polymerization, spectroscopic and flash photolysis study on novel water soluble methyl substituted 3-(9-oxo-9H-thioxanthene-2-yloxyl)N,N,N-trimethyl-1-propanaminium salts

摘要: Abstract The photopolymerization and photochemistry of seven novel water soluble methyl substituted 3-(9-oxo-9H-thioxanthene-2-yloxy)- N , -trimethyl-1-propanaminium salts are examined in 2-propanol using absorption, luminescence conventional microsecond flash photolysis techniques. In all cases, substitution enhances the 2-hydroxy-ethyl methacrylate water, 4-substitution being most effective. Longest wavelength absorption maxima extinction coefficients similar to those oil- water-soluble types studied earlier. fluorescence phosphorescence properties, on other hand, differ significantly. this case, quantum yields very similar, both processes strongly quenched by a group 1-position α carbonyl group. This effect is also reflected reduction triplet lifetime but not suppression activity. End-of pulse transient spectra overall weak exhibit two at about 340 440–520 μm. latter extremely normally associated with radical anion while former was difficult assign. Polymerization efficiency certainly correlated well below 400 nm, suggestive hydrogen atom abstraction primary initiated process. fact, end-of-pulse were little influenced presence tertiary amine, -diethylmethylamine, indicating predominence intra-molecular from trimethyl amino-group 2-position carbonyl. Transient only partly oxygen suggesting that photoreaction occurs main via lowest excited singlet state.