Popis: |
Resonance Raman spectra of p -hydroxyazobenzene, HO( p )C 6 H 4 NNC 6 H 5 , and its three ring-deuterated derivatives containing ( p )C 6 D 4 and/or C 6 D 5 have been recorded in the neutral and the alkaline pH regions. Based on the observed isotopic frequency shifts, the bands due to the p -disubstituted and monosubstituted rings have been distinguished clearly from each other. The spectral change on alkalifying the neutral solution shows that the contribution of the hydrazone structure in the resonance hybridization increases on the dissociation of a proton from the hydroxyl group. |