Synthesis, structural characterization, and chiroptical properties of planarly and axially chiral boranils

Chirality. 2023 Apr;35(4):227-246. doi: 10.1002/chir.23537. Epub 2023 Feb 3.

Abstract

2-Amino[2.2]paracyclophane reacts with salicylaldehyde or 2-hydroxyacetophenone to yield imines that then give access to a new series of boranils (8b-d) upon complexation with BF2 . These novel boron-containing compounds display both planar and axial chiralities and were examined experimentally and computationally. In particular, their photophysical and chiroptical properties were studied and compared to newly prepared, simpler boranils (9a-d) exhibiting axial chirality only. Less sophisticated chiral architectures were shown to demonstrate overall stronger circularly polarized luminescence (CPL) activity.

Keywords: axial chirality; boranil; density functional calculations; optical activity; planar chirality.