1,6-Photoaddition of toluene to 7,7,8,8-tetracyanoquinodimethane

Electron Donor-Acceptor Complexes in Their Excited States

“…According to the study by Bryce-Smith and his co-workers (Bryce-Smith, 1968;Bryce-Smith et al, 1970), the excitation in CT absorption of the complex between benzene and maleic anhydride gives the 1 : 2 addition product presumably via a zwitterionic intermediate: Yamasaki et al (1973) found that a 1,6-photoinduced addition of toluene to 7,7,8,8-tetracyanoquinodimethane (TCNQ) proceeds through a proton transfer step in the CT complex. Photoinduced addition has been studied in detail for the benzene-maleic anhydride system.…”

Synthetic Organic Photochemistry

“…(201.202) Similar results and interpretations have arisen from studies by Schaap(203) of 1,2-dioxetane formation via 9,1O-DCN-sensitized oxidations of alkenes and by Foote(204) of the methylene blue sensitized oxidative cleavage of t-stilbene. The detailed mechanisms for these oxidations appear to involve two key electron transfer steps, the first yielding the olefin cation radical-sensitizer anion radical pair (e.g.,271), and the second generating the superoxide ion and ground-state sensitizer by electron transfer to triplet oxygen. An alternate route involving capture of the olefin cation radical by ground-state oxygen is also possible.~hC~':CHPh DCA;"] ---+ rphC~!CHPh o;J ---+ ~ -?…”