Axially Chiral Heteroacenes for Chiral Light Control

Summer J. Brown, Ellen J. Forehand, Jioyan Zhao, Rupam Roy, Cedric Schaack, Austin M. Evans

University of Florida

Chiral organic chromophores can be used to control the spin-state of light.  Specifically, through the chiral induced spin-selectivity effect, one-handedness of polarized light interacting with chiral molecules can be preferentially transmitted through the medium.  This emerging phenomenon can be leveraged for access to new types of electronic devices.  Synthesizing and purifying these enantiopure chiral chromophores at a large scale ( >100 milligrams) has bottlenecked the promise of using chiral chromophores in a variety of these chiro-optical applications.   Additionally, tuning the wavelength of absorption and emission of these chiral compounds is challenging to achieve.  We circumvent this issue by creating a homochiral scaffold that can then be diversified without the need for chiral purification.  Using this scaffold, we have created both enantiomers of 10 different chiral chromophores based on a contorted heteroacene.  We are thus able to synthesize gram-scale quantities of our chiral chromophores and tune their optical absorption over a range of 150 nm which can be further tuned by a  pH switch in these species.  This strategy presents a method to prepare large quantities of enantiopure compounds and tune their optical profile.