Related Experiment Video
Updated: Sep 3, 2026

Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies
Published on: January 3, 2018
Bichromophores as a Molecular Platform to Explore Chiroptical Responses: Resonant Coupling and Beyond
Edakkandiyil Aiswarya1, Matteo Bedogni2, Meleppatt Sujith1
1School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram695 551, India.
Abstract:
Circular dichroism (CD) and circularly polarized luminescence (CPL) in molecular assemblies are governed by excited-state coupling spanning from on- to off-resonance regimes. Herein, these effects are investigated in bichromophoric systems where two 1,4-bis(phenylethynyl)benzene chromophores are arranged obliquely on RR- and SS-1,2-cyclohexanediamine scaffolds. The interaction is progressively detuned by varying the transition energy of one chromophore through substitution with diphenylacetylene or phenyl units, while retaining the other chromophore as 1,4-bis(phenylethynyl)benzene. The CD band shape evolves from bisignate to monosignate as exciton coupling changes from degenerate to quasi-degenerate and nondegenerate, since one of the CD peaks undergoes a hypsochromic shift and eventually leaves the spectral window of interest, concomitant with a decrease in gabs. All bichromophoric systems exhibit similar emission spectra, quantum yields, and lifetimes, whereas glum decreases upon detuning, indicating that CPL originates from 1,4-bis(phenylethynyl)benzene due to the chiral electrostatic environment imposed by the neighboring chromophore.
Related Concept Videos
Chirality in Nature
Channel Rhodopsins
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
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...
Prochirality
¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
UV–Vis Spectroscopy: Molecular Electronic Transitions
