Photoinduced reactions, molecular yield

In terms of photophysics, electron transfer reactions create an additional non-radiative pathway, so reducing the observed emission lifetimes and quantum yields in A-L-B dyads in comparison with a model compound. However, there are other processes, such as molecular rearrangements, proton transfer and heavy-atom effects, which may decrease the radiative ability of a compound. One of the most important experimental methods for studying photoinduced processes is emission spectroscopy. Emission is relatively easy to detect and emission intensities and lifetimes are sensitive to competing processes. Studying parameters such as emission quantum yields and lifetimes for a given supramolecular species and associated... 

Photochromic reactions of the heterocyclic fulgides are also in accordance with the Woodward-Hoffmann selection rules. The molecular structures have dramatic effects on the quantum yields of photoinduced ring-closure and ring-opening reactions of fulgides. The photochemical reactions of furyl fulgides are shown in Scheme 35 and the quantum yields are summarized in Table 4.29.44 45 104... 

Photoinduced electron-transfer reactions have also been observed in monolayer assemblies (23, 24). Such systems can be made essentially free of molecular diffusion and thus most closely resemble the solid state. They can be fabricated with precise geometry and therefore provide well-defined structures often lacking in amorphous solids or adsorbed layers. However, until now no evidence for enhancement of the yield of reaction (1) by added supersensitizers had been obtained, although the concept had been discussed (25). 

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