A redox-mediated molecular brake: dynamic NMR study of 2-[2-(methylthio)phenyl]isoindolin-1-one and S-oxidized counterparts.
A redox-mediated molecular brake based on the sulfide-sulfoxide redox cycle is illustrated by modulation of the rotation rate of an N-Ar "shaft" by varying the oxidation state of sulfur in 2-[2-(sulfur-substituted)phenyl]isoindolin-1-ones. N-Ar rotational barriers in methylsulfinyl (2) and methylsulfonyl (3) derivatives (13.6 kcal mol(-1)) are approximately 5 kcal mol(-1) higher than sulfide 1. Rate reduction for N-Ar rotation is approximately 10(4) s(-1) (280 K) upon oxidation. Correlated N-pyramidalization/N-Ar rotation reduces the effectiveness of the brake by decreasing the energy barrier to N-Ar bond rotation.
Jog
Parag V
PV
Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, USA.
Brown
Richard E
RE
Bates
Dallas K
DK