Fig. 1: Molecular structures, crystal structures and theoretical calculation results of (R/S)-OBN-XT-SXAC and (R/S)-OBN-XT-SFAC.

Molecular structures of a (R/S)-OBN-XT-SXAC and b (R/S)-OBN-XT-SFAC. Crystal structures of c (S)-OBN-XT-SXAC, d (R)-OBN-XT-SFAC and e (S)-OBN-XT-SFAC. The DFT-calculated HOMO and LUMO distributions, and energy difference of the S1 and T1 states of f (R)-OBN-XT-SXAC and g (R)-OBN-XT-SFAC.