In dichloromethane, two (+/-) Cotton effects were measured at 450 and 464 nm, with the lower energy band being less intense. The simulated average ECD spectrum predicts (+/-) signals at 417 and 443 nm with a less intense higher energy band (Figure ). We suggest that the difference in intensity between the measured spectra (where the higher energy band is more intensive) and calculated spectra (where the lower energy band is more intense) is due to ignoring dynamic effects; primarily changes in the position of Et groups, as shown above. Interestingly, the ECD spectrum of the main conformer C with the Cotton effects at 417 and 444 nm has almost the same intensity of these Cotton effects (Figure ).