Photochemical studies—II

Improving light fastness of natural dye: photostabilisation of gardenia blue

“…Gardenia blue (λ max = 598 nm) was supplied from Kiriya Chemical Co. Ltd (Japan). A series of benzoyloxy‐substituted benzene‐ and naphthalene‐sulphonate derivatives was synthesised by reaction of benzoyl chloride with the corresponding phenols or naphthols in a mixture of anhydrous N , N ‐dimethylformamide and pyridine, or in an anhydrous pyridine solution according to the procedures described in the literature [20]. The resulting aryl esters in sodium salt form were then purified by repeated recrystallisation from 50% acetic acid and identified by proton nuclear magnetic resonance ( 1 H‐NMR), infrared (IR) and elemental analyses.…”

Improvement of light fastness of natural dyes. Part 2: Effect of functional phenyl esters on the photofading of carthamin in polymeric substrate†

“…The nickel salt of p-toluenesulphonic acid (NTS; l max 233 nm) was prepared and purified as described previously [5]. Carthamin (l max 520, 380 nm) was supplied from San-eigen FFI Co. Ltd. A series of benzoyloxy-substituted benzene-and naphthalene-sulphonate derivatives was synthesised by reaction of benzoyl chloride with the corresponding phenols or naphthols in a mixture of anhydrous N,Ndimethylformamide and pyridine or in anhydrous pyridine solution according to the procedures described in the literature [7]. The resulting aryl esters in the sodium salt form were then purified by repeated recrystallisation from 50% acetic acid and identified by 1 H NMR, IR and elemental analyses.…”

Photochemical and Photophysical Studies of and in Bulk Polymers

“…These reactions offer an alternative method for the preparation of biaryls and alkyl aromatics, especially those in which the carbon center attached to the aromatic ring is chiral. 133 The decarboxylation products are formed by a concerted reaction of the excited -singlet state of the aryl esters in which the stereochemistry of the carbon atom adjacent to the carboxy carbon is retained in the decarboxylated photoproduct (Chart 11.11 ); photoFries or decarbonylated photoproducts are formed from stepwise reactions involving radical pairs (Scheme 11.14 ).…”