Circularly polarized luminescence of pinene-modified tetradentate platinum(II) enantiomers containing fused 5/6/6 metallocycles

Hua-Hong Zhang; Jing Jing; Guo Xu; Yi-Xin Song; Shui-Xing Wu; Xing-Han Chen; Da-Shuai Zhang; Xiao-Peng Zhang; Zai-Feng Shi

doi:10.1016/j.heliyon.2022.e11358

Circularly polarized luminescence of pinene-modified tetradentate platinum(II) enantiomers containing fused 5/6/6 metallocycles

Heliyon. 2022 Nov 3;8(11):e11358. doi: 10.1016/j.heliyon.2022.e11358. eCollection 2022 Nov.

Authors

Hua-Hong Zhang¹, Jing Jing¹, Guo Xu¹, Yi-Xin Song¹, Shui-Xing Wu¹, Xing-Han Chen², Da-Shuai Zhang¹, Xiao-Peng Zhang¹, Zai-Feng Shi¹

Affiliations

¹ College of Chemistry and Chemical Engineering, Key Laboratory of Water Pollution Treatment & Resource Reuse of Hainan Province, Hainan Normal University, Haikou 571158, PR China.
² Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, PR China.

Abstract

In this study, a couple of tetradentate Pt(II) enantiomers ((-)-1 and (+)-1) and a couple of tetradentate Pt(IV) enantiomers ((-)-2 and (+)-2) containing fused 5/6/6 metallocycles have been synthesized by controlling reaction conditions. Two valence forms could transform into each other through mild chemical oxidants and reductants. Single-crystal X-ray diffraction confirms the structures of (-)-1 and (-)-2. The coordination sphere of the Pt(II) cation in (-)-1 displays a distorted square-planar geometry and a platinum centroid helix chirality. In contrast, the structure of (-)-2 reveals a distorted octahedral geometry. The solution and the solid of (-)-1 are highly luminescent. Complex (-)-1 shows a prominent aggregation-induced emission enhancement (AIEE) behavior in DMSO/water solution with emission quantum yield (Φ _em) up to 73.2%. Furthermore, highly phosphorescent Pt(II) enantiomers exhibit significant circularly polarized luminescence (CPL) with a dissymmetry factor (g _lum) of order 10^-3 in CH₂Cl₂ solutions at room temperature. Symmetrically appreciable CPL signals are observed for the enantiomers (-)-1 and (+)-1.

Keywords: Aggregation-induced emission enhancement; Circularly polarized luminescence; Fused metallocycles; Pinene; Tetradentate platinum(II) complex.