Pyrroles photoisomerization

Later, Falk [66] used TET to explain the photoisomerization of pyrrole pigments. Markov [67] applied the theory to photoketonization of dicarbonylic compounds. Hamanoue [68] showed that TET predictions were consistent with the relative reactivity of (n, n ) and (n, Tt ) states of an-thraquinones. Following a suggestion by Isaacs [69], Okamoto [70] claimed that the increase in the KIE of the H abstraction of methanol by benzo-phenone was evidence for a nuclear tunnelling mechanism, but this claim is not entirely consistent with the predictions of Isaacs. Shizuka [71] proposed TET could be used to explain excited state proton transfers, but this may only be the case for intramolecular proton transfers or reactions in apolar solvents, otherwise the system effective reduced mass will be too high [72]. 

Photoisomerizations of numerous substituted thiophenes, as well as of furans and pyrroles, are known. 

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