Mukhopadhyay, Arindam Jana, Kanyashree Hossen, Tousif Sahu, Kalyanasis Moorthy, Jarugu Narasimha Coumarin-Annelated Regioisomeric Heptahelicenes: Influence of Helicity on Excited-State Properties and Chiroptical Properties Two regioisomeric pairs of heptahelical mono- and biscoumarins that are differentiated by “<i>inward</i>” and “<i>outward</i>” disposition of the pyran-2-one moiety have been synthesized and investigated to understand the influence of helicity on excited-state and chiroptical properties. A slight variation in the helicities is found to manifest in contrasting excited-state properties of coumarin-annelated heptahelicenes; in addition to the intramolecular charge transfer, structural relaxation in the excited state is shown from theoretical calculations to cause decrease in the fluorescence quantum yield for a system with higher helicity. The optically pure enantiomers of heptahelical coumarins exhibit helicity-dependent chiroptical properties, namely, specific rotations, molar ellipticities, Cotton effects, and anisotropic dissymmetry factors. Theoretical calculations point to factors that are not readily explicable. excited-state properties;molar ellipticities;pyran -2-one moiety;Coumarin-Annelated Regioisomeric Heptahelicenes;regioisomeric pairs;Excited-State Properties;intramolecular charge transfer;anisotropic dissymmetry factors;cause decrease;chiroptical properties;heptahelical coumarins exhibit helicity-dependent chiroptical properties;Chiroptical Properties;Theoretical calculations point;Cotton effects;coumarin-annelated heptahelicenes;fluorescence quantum 2019-08-22
    https://acs.figshare.com/articles/dataset/Coumarin-Annelated_Regioisomeric_Heptahelicenes_Influence_of_Helicity_on_Excited-State_Properties_and_Chiroptical_Properties/9710180
10.1021/acs.joc.9b01126.s006