The element effect in nucleophilic aromatic photosubstitution (SN2Ar*).
Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen = F, Cl, Br, I) with NaCN have been investigated. 4-Nitroanisole gave a novel, stable nitronate ion adduct (74%) with cyanide. For the five compounds, we report product distributions, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields, which afford rate constants for attack by the cyanide ion. Cyanide attack on the fluoride is diffusion controlled; the relative rates for attack at F, Cl, Br, and I are 27:2:2:1, respectively.
Wubbels
Gene G
GG
Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, USA. wubbelsg@unk.edu
Johnson
Kandra M
KM
Babcock
Travis A
TA