Enhanced N-directed electrophilic C–H borylation generates BN–[5]- and [6]helicenes with improved photophysical properties
Kang Yuan, Daniel Volland, Sven Kirschner, Marina Uzelac, Gary S. Nichol, Agnieszka Nowak‐Król, Michael J. Ingleson
Abstract
. The synthesised helicenes include BN-analogues of archetypal all carbon [5]- and [6]helicenes. The replacement of a CC with a BN unit (that has a longer bond) on the outer helix increases the strain in the BN congeners and the racemization half-life for a BN-[5]helicene relative to the all carbon [5]helicene. BN incorporation also increases the fluorescence efficiency of the helicenes, a direct effect of BN incorporation altering the distribution of the key frontier orbitals across the helical backbone relative to carbo-helicenes.
Topics & Concepts
BorylationElectrophileChemistryCombinatorial chemistryStereochemistryOrganic chemistryArylCatalysisAlkylOrganoboron and organosilicon chemistrySynthesis and Properties of Aromatic CompoundsLuminescence and Fluorescent Materials