Circular Dichroism (CD) to Determine %ee
One of the truly interesting aspects of this experiment comes
from taking CD spectra of the Λ- and Δ-Co(en)3
3+ and the Λ-
and Δ-Co(diNOsar)3+ products. We use CD rather than
polarimetry at this point due to its beautiful high precision
spectra, sensitivity, and pedagogical value in teaching advanced
analytical and inorganic topics to undergraduate students. The
most striking (and initially disturbing) observation when we record
the CD data is that the Λ-Co(diNOsar)Br3 product and the Λ-
Co(en)3I3 starting material f rom which it is produced show
opposite sign of the molar ellipticity of the major absorption
centered near 490 nm (see Figure 4).