Eosin dimerization

An entirely different light-induced reaction occurs when ergosterol is irradiated in the presence of a sensitizer such as eosin. The product is a dimer (27) [ 18]. This is a relatively low-... 

Absorption and fluorescence spectra of 7-aminocoumarin derivatives have been recorded and the photophysics of coumarin inclusion complexes with 0- and y-cyclodextrins investigated. Solvent effects on the photophysical behaviour of pyrrolocoumarin derivatives are similar to those on the psorolens . Vibronic exciton bands and the absorption spectra of Eosin Y dimers have been analysed theoretically and compared with experimental data. Picosecond spectroscopic studies have been made on the ionic photodissociation dynamics of malachite green leucocyanide . The lowest state produces ions within 0.1 to 0.5 ns whilst for higher states 6-13 ps are sufficient for the development of charge separation. The photophysics of crystal violet in a series of n-... 

Similar to anthracene, acenaphthylene can also be encapsulated by [78]2 to form a 2 2 complex. NMR studies suggested that two acenaphthylene molecules are located in the middle of the capsule cavity and oriented in a parallel fashion. Irradiation of acenaphthylene in the absence of any host yielded syn- and ani/-dimers, with the latter being the major product. Within the [78]2 cavity, only iyn-dimer 79 was obtained upon irradiation. In the presence of triplet sensitizer eosin-Y, irradiation of the complex gave syn- and anti-dimers in a ratio 60 40. 

Scheme 1.1. Effects of heat, light, and acid in the presence of oxygen on the dimeric Strychnos alkaloids. Reagents a. O2 + A, or O2 + hv b. O2 + hv + eosin, or O2 + pyr/AcOH c. O2, H30. ...

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