Variable temperature NMR studies, undertaken to enable the resolution of signals for the equilibrating valence tautomers revealed interesting shifts in the equilibrium of the norcaradiene-cycloheptatriene-NCD-CHT equilibrium.
Original citation BATEMAN, L. M., MCNAMARA, O. A., BUCKLEY, N. R., O'LEARY, P., HARRINGTON, F., KELLY, N., O'KEEFFE, S., STACK, A., O'NEILL, S., MCCARTHY, D. G. & MAGUIRE, A. R. 2015. A study of the norcaradiene-cycloheptatriene equilibrium in a series of azulenones by NMR spectroscopy; the impact of substitution on the position of equilibrium. Organic & Biomolecular Chemistry, 13, 11026-11038. http://dx.doi.org/10.1039/C5OB01346A