85013-24-7Relevant articles and documents
Substituent Effects on Tautomerisation Constants of Alkylaryltriazenes
Kelly, Miguel A.,Murray, Martin,Sinnott, Michael L.
, p. 1649 - 1654 (2007/10/02)
Both tautomers of propyl-p-nitrophenyl-, -p-cyanophenyl-, -3,5-dichlorophenyl-, and -p-chlorophenyl-triazenes are directly observable by 1H n.m.r. at 200 MHz in CD3CN at 25 deg C.In addition, lower temperature studies enable the two tautomers of propyl-p-methylphenyl- and -p-methoxyphenyl-triazenes to be quantitated.At -45 deg C rotamers about the N-N bond of the conjugated tautomers are also separately observable. 13C N.m.r. studies of the p-nitro- and p-chloro-compounds suggest tautomerisation involves the less abundant rotamer of the conjugated tautomer and the unconjugated tautomer.The position of equilibrium at 25 deg C is described by log (/) = (0.67 +/- 0.13) - (0.31 +/- 0.04)pKa (ArNH3+). 13C, as well as 1H n.m.r. studies indicate that change of solvent to (CD3)2SO, CD3CN-(CD3)2SO, or CD3CN-(CD3)2SO-H2O has little effect.Neither, in the p-nitrophenyl case, does change of the propyl group for benzyl.