Fig. 3.

Ring inversion kinetics of ^Th4 COT _Saddle and ^Th6 CDH _Screw. a, b, Time-dependent CD spectral change profiles (240-s interval) of ^Th4 COT _Saddle (a) and ^Th6 CDH _Screw (b) in methylcyclohexane at 60 and 0 °C, respectively. Black arrows in a and b represent the directions of the CD spectral change with time. c, d, Decay profiles of the CD intensities at 260 nm (c, ^Th4 COT _Saddle) and 280 nm (d, ^Th6 CDH _Screw) in deaerated methylcyclohexane at 20 and −20 °C, respectively. Blue-colored dots represent decay profiles without photoirradiation. Orange-colored dots represent decay profiles with photoirradiation (λ = 365 ± 5 nm). Green-colored dots represent decay profiles with photoirradiation (λ = 420 ± 5 nm) in the presence of fluorenone (0.34 equiv. for ^Th4 COT _Saddle and 0.23 equiv. for ^Th6 CDH _Screw). Photoirradiation (250 s, red vertical lines) and CD spectroscopy (50 s, white area between red vertical lines) were conducted alternately for 6000 s