Abstract
This chapter focuses on the five membered monoheterocyclic compounds of the indigo group. The electronic absorption characteristics of many dye molecules containing an unsaturated five-membered ring system is explained in terms of their anti-aromaticity. A one pot synthesis of indigo involves the oxidation of indole with an organic hydroperoxide in the presence of a molybdenum complex. The chapter also reviews the photoisomerism and photochemistry of indigo, its derivatives and related compounds. Indigo is stable to photoinduced trans → cis isomerization, but when the hydrogen atoms of the NH groups are replaced by methyl, or acetyl, functions phototropic mobility is induced. This is explained by loss of hydrogen-bonding to the oxygen atoms of the carbonyl units but a proton-transfer between NH and CO groups in the excited singlet state is also proposed as a pathway for rapid radiationless decay.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
