A new
series of axially chiral binuclear Pt(II) complexes with
bridging ligands of binaphthalenes and octahydro-binaphthalenes and
auxiliary ligands of β-diketones were designed and prepared.
These complexes, identified by spectral and electrochemical methods
and single-crystal X-ray diffraction, emit an orange-red phosphorescence
with a quantum yield up to 21% and 70% in solution and solid, respectively,
due to the effect of steric hindrance from bridging ligands and the
2,3-position extension of chiral axis planes. They can be used as
emitters in solution-processed organic light-emitting diodes to achieve
luminance efficiency, asymmetry factor, and external quantum efficiency
up to 5.4 cd A–1, 3.0 × 10–3, and 3.1%, respectively. Moreover, the essential relationships between
their chemical structures and luminescence quantum efficiency and
asymmetry factor are discussed, which affords explicit insights for
designing circularly polarized luminescent materials and devices.