Enhanced Circularly Polarized Luminescence Activity in Chiral Platinum(II) Complexes With Bis- or Triphenylphosphine Ligands
Qian-Ying Yang, Hua-Hong Zhang, Xueling Han, Shi-Dao Weng, Yuan Chen, Jiali Wu, Li-Zhi Han, Xiao-Peng Zhang, Zaifeng Shi
Abstract
Distinct circularly polarized luminescence (CPL) activity was observed in chiral (C^N^N)Pt(II) ([C^N^N] = 4,5-pinene-6'-phenyl-2,2'-bipyridine) complexes with bis- or tri-phenylphosphine ligands. Compared to pseudo square-planar geometry of chiral (C^N^N)Pt(II) complexes with chloride, phenylacetylene (PPV) and 2,6-dimethylphenyl isocyanide (Dmpi) ligands, the coordination configuration around Pt(II) nucleus of chiral (C^N^N)Pt(II) complexes with bulk phosphine ligands is far more distorted. The geometry is straightforwardly confirmed by X-ray crystallography. The phosphines’ participation enhanced the CPL signal of Pt(II) complexes profoundly, with the dissymmetry factor (glum) up to 10-3. The distorted structures and enhanced chiroptical signals was further confirmed by TD-DFT calculations.