Photo... s. a. Irradiation

The (chemical) actinometer A (Figure 7.40), is a photo reactive sample of known quantum yield a. For the determination of the quantum yield of the unknown sample S, this sample and the actinometer are irradiated simultaneously through the beam splitter B, which divides the incoming beam in a ratio rA, which is independent of time and of light intensity. The change of concentration, Ac(A), of the actinometer gives the number of photons absorbed, so that the quantum yield of the unknown reaction is obtained as the ratio of the concentration changes... 

The photoisomerisation kinetics and other properties of the 1 1 inclusion complexes formed between aromatic derivatives of norbomadiene and P-cyclo-dextrin have been measured." (S)- or (R)-2-Chloropropiophenone affords partially racemised (S)- or (R)-2-phenylpropionic acid respectively by a photo-induced rearrangement via what is probably an ion or radieal intermediate," and (Z)-N-substituted benzoyl-a-dehydrophenylalanines such as (7) are photo-isomerised to 1-azetidine derivatives (8) by a 1,3-acyl migration. Irradiation of 9,9 -bifluorene-9,9 -diol (9) gives a mixture of fluoren-9-one and spiro[9H-fluorene-9,9 (10 -H)-phenanthren]-10 -one (10) whose composition is solvent dependent with the more polar solvents favouring (10). Laser flash photolysis shows the presence of two transients, one of which can be identified with the 9-fluorenyl cation (11), and which originates from photoheterolysis of the diol (9). There is also evidence to support the view that unimolecular rearrange-... 

FIGURE 54.19 Schematic illustration of pH-dependent micellization of PEG-fc-P(DEAEMA/CEA) and the formation of a nanogel with UV-irradiation. (Reprinted with permission from Langmuir, 25(9), Ynsa, S.I., Sugahara, M., Endo, T., and Morishima, Y., Preparation and characterization of a pH-responsive nanogel based on a photo-crosslinked micelle formed from block copolymers with controlled strnctnre, 5258. Copyright 2009 American Chemical Society.)... 

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