Wasserlösliche disulfonierte aromatische Ketone — Photophsikalische und photochemische Eigenschaften

Abstract

Water Soluble Disulphonated Aromatic Ketones — Photophysical and Photochemical Properties By the sulphonation of benzophenone, xanthone, thioxanthone, acridone, and methylacridone the disulphonated derivatives BPS, XS, TXS, AcS and MAcS are produced. Their disodium salts are well soluble in water. The absorption and the emission spectral data of these ketones are similar to those of the respective parent compounds. The S1 state of BPS alone is of n — π* type, in all the other cases it possesses mainly π — π* character. The S1 states can serve as donors in electron transfer reactions with iodonium salts. The kinetic curves of flash photolysis of these ketones in water show two decay processes, which are attributed to the triplet state and the long living ketyl radical. The triplet absorption spectra of the disulphonated ketones are very close to those of the unsubstituted ketones, but the life times of the former are much higher. The T1 are quenched through onium salts by electron transfer reactions. Acryl amide, too, acts as a quencher for the triplets.

Hydrogel formation by photocrosslinking of dimethylmaleimide functionalized polyacrylamide

“…1 TXS as introduced by Gupta et al [67] was chosen as water-soluble triplet sensitizer. Its properties have been studied by Kronfeld and Timpe [59], whose approach for synthesis and characterization was followed here. The product was obtained as a mixture with Na 2 SO 4 containing about 4 wt.% TXS (sodium salt).…”

“…In the present work, we employed the sodium salt of thioxanthone disulfonate. The sulfonate groups only act in terms of increasing the water solubility without affecting the spectral properties significantly [59,66].…”

“…The energy of their T 1 state is relatively high [50,63] and only marginally less than that of S 1 . Intersystem crossing occurs with high quantum yield [63e65], and they show adequately long triplet lifetimes [59]. In the present work, we employed the sodium salt of thioxanthone disulfonate.…”

“…Molecules with pp* triplet states are therefore preferred as sensitizers, because unwanted reactions can be largely excluded. There have been several studies showing that the T 1 state of thioxanthones in polar media corresponds to a pp* transition [59,60]. Thioxanthones have been widely used for photosensitization and initiation purposes [61,62].…”

Additive Soft Matter Design by UV-Induced Polymer Hydrogel Inter-Crosslinking

“…The synthesis of TXS was adopted from Ref. [20]. In short, 5 g thioxanthen-9-one was dissolved in 100 mL fuming sulfuric acid and refluxed for 3.5 h at 110 • C. The solution was cooled down, poured on 300 g ice, and neutralized by adding CaCO 3 , until CO 2 production stopped.…”