Interactivity box 2. Selected molecular orbitals involved in the ECD bands in 5 and 6.a
(R,R)-5 (R,R)-6
  • The 280nm transition (Δε +ve Cotton effect) is (predominantly)b due to excitation from orbital 8486 (superimposed).
  • The 230nm transition (Δε -ve Cotton effect) comprises orbital 8488 (view superimposed).
For the high energy bands (230 or 225nm) the originating orbitals (84 or 76) are very similar but the accepting orbitals (88 or 80) differ quantitatively. Larger, qualitative differences occur for the low energy bands (280 or 272 nm).
a Calculated (M062X/6-311++G(d,p)/SCRF=1,4-dioxane) orbitals corresponding to the ECD transitions observed for 5 and 6. The occupied orbital is shown with orange/purple phases, and the unoccupied with red/blue phases. Full details on the TDDFT ECD calculation can be obtained from a digital repository by following the resolvers: 5 10042/24704, 6 10042/24705.bThe excited states arise from excitations from several molecular orbitals. For example, in 6 the 272nm band is only approximately 73→77. The full list is 70 →77 (0.13139), 72 → 77 (0.17252), 73 → 77 (0.51311), 74 → 77 (0.28794), 76 → 78 (0.16035). For full details, see the outputs available in the digital repository entries.