SUCCINIMIDYLATION AND NITRATION OF AROMATIC-COMPOUNDS BY PHOTOLYSIS WITH N-NITROSUCCINIMIDE

N-Nitrosuccinimide (S-NO2) engages in weak charge transfer complexes with aromatic compounds (ArH). Upon photolysis with light of lambda > 345 nm in dichloromethane, electron transfer within the charge transfer complex leads to the triad [(ArHS-NO2)-S-.+] from which products of eventual succinimidylation and/or nitration develop by initial attack of succinimide anion upon the radical cation. Photolysis in the presence of trifluoroacetic acid (0.4 mol dm(-3)) causes inactivation of S- by protonation, making EPR detection of ArH.+ or radical cations formed by its further transformations possible. In acetonitrile, trifluoroacetic acid is too weak effectively to protonate S-, whereas addition of stronger acids again leads to the development of EPR spectra of ArH.+ in the case of 9,10-dimethylanthracene, the intensity increasing with decreasing pK of the acid. An X-ray crystal structure is reported for N-nitrosuccinimide.