149883-58-9Relevant academic research and scientific papers
Electronic Structure of Symmetric Homocojugated Dienes. Circular Dichroism of (1S)-2-Deuterio- and 2-Methylnorbornadiene and (1S)-2-Deuterio- and 2-Methylbicyclooctadiene
Lightner, David A.,Gawronski, Jacek K.,Bouman, Thomas D.
, p. 5749 - 5754 (1980)
(1S)-Bicyclohepta-2,5-diene (1), (1S)-2-methylbicyclohepta-2,5-diene (3), (1S)-bicycloocta-2,5-diene (4), and (1S)-2-methylbicyclooctadiene (6) were prepared by reaction of the corresponding chiral β,γ-unsaturated ketone tosylhydrazone with CH3Li followed by either D2O or CH3I quenching.The circular dichroism Cotton effects of 1 (Δε237 = -0.032, Δε216 = +0.14, Δε205 = -0.37) and 4 (Δε222 = -0.027) are the first examples obtained from deuterated olefins or dienes whose chirality is due only to isotopic substitution.Both the deuterated and the methylated dienes exhibited multiple Cotton effects (3, Δε249 = +2.38, Δε222 = -0.25, Δε219 = -0.54, Δε214 = +0.62, Δε204 = -0.94; 6, Δε231 = +0.90, Δε211 = +0.48, Δε200 = -0.24), demonstrating the existence of interchromophoric interaction and electronic transitions that are only difficulty seen in their ultraviolet spectra.We present ab initio localized orbital RPA calculations on 1 that allow a consistent assignment of norbornadiene transitions.
