%0 Generic
%A Mukhopadhyay, Arindam
%A Jana, Kanyashree
%A Hossen, Tousif
%A Sahu, Kalyanasis
%A Moorthy, Jarugu Narasimha
%D 2019
%T Coumarin-Annelated Regioisomeric
Heptahelicenes: Influence
of Helicity on Excited-State Properties and Chiroptical Properties
%U https://acs.figshare.com/articles/dataset/Coumarin-Annelated_Regioisomeric_Heptahelicenes_Influence_of_Helicity_on_Excited-State_Properties_and_Chiroptical_Properties/9710180
%R 10.1021/acs.joc.9b01126.s006
%2 https://acs.figshare.com/ndownloader/files/17399231
%K excited-state properties
%K molar ellipticities
%K pyran -2-one moiety
%K Coumarin-Annelated Regioisomeric Heptahelicenes
%K regioisomeric pairs
%K Excited-State Properties
%K intramolecular charge transfer
%K anisotropic dissymmetry factors
%K cause decrease
%K chiroptical properties
%K heptahelical coumarins exhibit helicity-dependent chiroptical properties
%K Chiroptical Properties
%K Theoretical calculations point
%K Cotton effects
%K coumarin-annelated heptahelicenes
%K fluorescence quantum
%X Two
regioisomeric pairs of heptahelical mono- and biscoumarins
that are differentiated by “inward”
and “outward” 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.
%I ACS Publications