posted on 2021-04-26, 20:05authored byGonzalo Campillo-Alvarado, Rachel J. Liu, Daniel W. Davies, Ying Diao
We
describe the use of perfluorophenyl embraces and boron coordination
(B ← N) to enhance dichroism in single crystals of an asymmetric
azo chromophore. Specifically, a tripod-shaped boron adduct comprised
of tris(pentafluorophenyl)borane (BCF) and 4-phenylazopyridine
(4PAzP) self-assembles as supramolecular helices through
perfluorophenyl embraces, wherein the azo chromophores are aligned
in parallel through B ← N bonds. The alignment of molecular
transition dipole moments in (BCF)·(4PAzP) results in enhanced dichroism compared to pure 4PAzP as confirmed by polarized optical microscopy. The study offers a
novel supramolecular strategy to enhance dichroism in single-crystalline
materials.