Indolyl fulgides

Yokoyama and Kurita demonstrated the design, synthesis, and photochromic behavior of 5-substituted indolyl fulgides (56). The molecular structure and photochromic reactions are shown as Scheme 17. 

Substituent effects on the quantum yield of photoreactions of indolyl fulgide 58 have also been reported by Uchida et al.,15 as shown in Table 4.14. The molecular structure and photochromic reactions are shown in Scheme 18. 

Table 4.13. Absorption Spectra Data and Quantum Yields of Photoreactions of Indolyl Fulgide 56 (Z, E) and its Colored Form (57) (C) in Toluene...

The data in Table 4.26 indicate that when the steric hindrance of R1 was increased, the quantum yields of Ef>Z photoisomerization decreased, but the steric hindrance effect of R2 was not clear. The quantum yields of E ftZ isomerization for indolyl fulgides in toluene are summarized in Table 4.27. The reaction is shown in Scheme 31. 

Table 4.27. Quantum Yields of E Z Photoisomerization of Indolyl Fulgides 85 in Toluene (Irradiated at 405 nm) ...

Table 4.30. Quantum Yields of Photoreactions of Indolyl Fulgides 90...

H. Z. Wang, Synthesis and photochromic reactions of indolyl fulgides, Doctoral dissertation, Beijing Institute of Technology, Beijing, China (1989). 

Y. Yokoyama, T. Tanaka, T. Yamane, and Y. Kurita, Synthesis and pliotochromic behavior of 5-substituted indolyl fulgides, Chem. Lett., 1991, 1125-1128. 

S. Uchida, S. Yamada, Y. Yokoyama, and Y. Kurita, Steric effects of substituents on the photochromism of indolyl fulgide, Bull. Chem. Soc.Jpn., 68, 1677-1682 (1995). 

Scheme 7. Acid-gated photochromic reactions of an indolyl fulgide 35 with a dimethylamino...

Liang, Y.C., Dvornikov, A.S., and Rentzepis, P.M., Photochemistry oF photochromic 2-indolyl-Fulgides with substituents at the 1-position oF the indolyhnethylene moiety, J. Photochem. Photobiol. A Chem., 146, 83, 2001. 

Indolyl-substituted heterocyclic fulgides have been studied by several research groups.65-69 Wang et al.10 and Fan et al11 reported the synthesis and crystal structures of azafulgide 54. The structures and photochromic reactions are shown in Scheme 16. 

Indolyl fulgenate is a new kind of photochromic compound. The EvaZ photoisomerization is also involved, as shown in Scheme 32. The quantum yields of EvaZ photoisomerization are summarized in Table 4.28. In general, the quantum yields of E va Z photoisomerization of fulgide and its derivatives are much lower than those of photocyclization (see Section 4.5.3). 

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