Reactivities of acridine compounds in hydride transfer reactions

초록

Reactivities of acridine derivatives (10-benzylacridinium ion, 1a(+), 10-methylacridinium ion, 1b(+), and 10-methyl-9-phenylacridinium ion, 1c(+)) have been compared quantitatively for hydride transfer reactions with 1,3-dimethyl-2-substituted phenylbenzimidazoline compounds, 2Ha-h. Reactions were monitored spectrophotometrically in a solvent consisting of four parts of 2-propanol to one part of water by volume at 25 +/- 0.1 degrees C. Reduction potentials have been estimated for acridine derivatives by assuming that the equilibrium constants for the reductions of 1a(+)-c(+) by 2Hb would be the same in aqueous solution and accepting -361 mV as the reduction potential of the 1-benzyl-3-carbamoylpyridinium ion. The resulting reduction potentials, E-red(o), are -47 mV for 1a(+), -79 mV for 1b(+), and -86 mV for 1c(+). Each of acridine derivatives gives a linear Bronsted. plot for hydride transfer reactions. The experimental slopes were compared with those obtained by Marcus theory. This comparison shows that the kinetic data are consistent with a one-step mechanism involving no high-energy intermediates. Copyright (c) 2007 John Wiley & Sons, Ltd.

키워드