Easy separation of Δ and Λ isomers of highly luminescent [Ir III]-cyclometalated complexes based on chiral phenol-oxazoline ancillary ligands

Abstract

A new class of neutral cyclometalated iridium(III) complexes with enantiomerically pure C 1-symmetric phenol-oxazolines (3 a,b) have been synthetized in high yields and fully characterized. Resolution of the corresponding Δ R and Λ R or Δ S and Λ S isomers was easily achieved by conventional flash chromatography. The corresponding Δ and Λ helicities have been confirmed by CD spectroscopy and X-ray crystallography. Regarding the absorption and luminescence properties with unpolarized light, no significant difference between Δ and Λ isomers has been observed. A strong blue luminescence is observed for deaerated solutions of complexes 5 a and 5 b in CH 3CN. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.