Related Experiment Video
Updated: Oct 10, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Chiral exciplex dyes showing circularly polarized luminescence: extension of the excimer chirality rule
Kazuto Takaishi1, Sho Murakami1, Kazuhiro Iwachido1
1Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Tsushima Okayama 700-8530 Japan takaishi@okayama-u.ac.jp ema@cc.okayama-u.ac.jp.
Abstract:
A series of axially chiral binaphthyls and quaternaphthyls possessing two kinds of aromatic fluorophores, such as pyrenyl, perylenyl, and 4-(dimethylamino)phenyl groups, arranged alternately were synthesized by a divergent method. In the excited state, the fluorophores selectively formed a unidirectionally twisted exciplex (excited heterodimer) by a cumulative steric effect and exhibited circularly polarized luminescence (CPL). They are the first examples of a monomolecular exciplex CPL dye. This versatile method for producing exciplex CPL dyes also improved fluorescence intensity, and the CPL properties were not very sensitive to the solvent or to the temperature owing to the conformationally rigid exciplex. This systematic study allowed us to confirm that the excimer chirality rule can be applied to the exciplex dyes: left- and right-handed exciplexes with a twist angle of less than 90° exhibit (-)- and (+)-CPL, respectively.
Related Concept Videos
Molecules with Multiple Chiral Centers
Properties of Enantiomers and Optical Activity
Chirality in Nature
Chirality
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chirality at Nitrogen, Phosphorus, and Sulfur
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation

