A study of planar chromophores in dichromophoric molecules by circular dichroism spectroscopy.

A synthesis of a series of enantiomerically pure polycyclic structures derived from (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione was accomplished. Molecules containing single or two similar or different chromophores were obtained. Chiroptical properties of the synthesized chiral structures 2-5, and 7 having carbonyl, 1,2-methylenedioxybenzene, and indole chromophores were studied. The sign of the cotton effect was related to sector rules and the orientation of the planes containing chromophores in dichromophoric molecules possessing 1,2-methylenedioxybenzene and carbonyl or indole chromophores. Interaction of the chromophores in dichromophoric molecules was examined by CD spectroscopy; however, no direct evidence was obtained.