Determination of the Helical Screw Sense and Side-Group Chirality of a Synthetic CMral Polymer from Raman Optical Activity

摘要

The structures and conformations of the backbones of synthetic polymers exert a major influence on their solution and bulk properties. Among other techniques, infrared and Raman spectroscopy have been extensively used in their study. Owing to growing interest in the unique properties of chiral and especially helically chiral polymers, chiroptical methods like electronic circular dichroism (ECD) have also become standard techniques in polymer chemistry.Recently the chiroptical versions of infrared and Raman spectroscopy, namely vibrational circular dichroism (VCD) and Raman optical activity (ROA), which measure vibrational optical activity (VOA), have attracted widespread interest. While VCD measures the differential absorption of left- and right-circularly polarized infrared radiation by a chiral sample, ROA may be measured either as a small difference in the Raman scattering of right- and left-circularly polarized incident radiation (incident circular polarization (ICP) ROA) or as a small circularly polarized component in the Raman scattered radiation (scattered circular polarization (SCP) ROA).