Fig. 7. 1H–1H NOESY spectra showing dependence of Ru–NHC rotation on NHC unsaturation. (a) Exchange correlations between mesityl methyl signals for the IMes derivatives. (b) Absence of correlations for the H2IMes analogues. (all in C6D6, 500.1 MHz, 25 °C, 1.5 s relaxation delay). Symbols: (^) = Cy; for others, see top.
