# THE VIBRATIONAL CIRCULAR DICHROISM SPECTRUM OF 2-METHYLTHIETANE

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 Title: THE VIBRATIONAL CIRCULAR DICHROISM SPECTRUM OF 2-METHYLTHIETANE Creators: Shaw, R. A.; Ibrahim, N.; Wieser, H. Issue Date: 1990 Publisher: Ohio State University Abstract: The vibrational circular dichroism (VCD) spectrum is reported for 2-methylthietane in the region of $800-1500 cm^{-1}$. Based on optimized geometries and force fields at the 3-21G and 6-31G levels of ab initio theory for the equatorial and axial $confomers,^{1}$ the infrared absorption and VCD intensities are calculated with the Fixed Partial Charge (FPC), Charge Flow (CF), and Atomic Polar Tensor (APT) models. Empirically a distinction can be made for selected modes that can be used as reliable configuration markers being insensitive to conformation change, and conformation indicators reversing the VCD sign upon ring inversion while being insensitive to the absolute configuration. Generally none of the three VCD models agree with all the observed VCD features. From the inability to predict the VCD intensities of specific modes and by comparison with analogous situations for $2-methyloxetane,^{2}$ inferences are drawn about the adequacy of the models in certain circumstances Description: $^{1}$ R.A. Shaw, N. Ibrahim, and H. Wieser, Can. J. Chem., in press. $^{2}$ R.A. Shaw, N. Ibrahim, and H. Wieser 94, 125-133(1990). Author Institution: Department of Chemistry, University of Calgary URI: http://hdl.handle.net/1811/18326 Other Identifiers: 1990-TG'-8