We report the synthesis and characterization of two chiral binuclear iridium(III) complexes (ΛΛ and ΔΔ) prepared from enantiopure building blocks [μ-Cl₂(Δ-Ir(C^N)₂)₂] and [μ-Cl₂(Λ-Ir(C^N)₂)₂]. These building blocks have been obtained by chiral preparative high-performance liquid chromatography of the neutral iridium(III) complex Irpiv (piv = 2,2,6,6-tetramethylheptane-3,5-dionate) followed by selective degradation of the ancillary ligand. For comparison purposes, we also synthesized a monomer (IrL¹) and a dimer (Ir₂L², mixture). All the complexes exhibit similar emission properties, emitting in the orange-red region of the spectra with a good photoluminescence quantum yield (λ_max = 610–625 nm, Φ ∼ 25%, τ ∼ 800–900 ns). However, the ΛΛ and ΔΔ complexes are optically active, indicating that no isomerization occurred during the different synthetic steps, as evidenced by both the circular dichroism spectra and their circularly polarized luminescence (CPL). The capital gain of the dimers (Ir₂L², ΛΛ, and ΔΔ) is a 4-fold brightness (B₃₈₀ = ε_380 nm × Φ) compared to the monomer (IrL¹) and the CPL brightness (B_CPL = B₃₈₀ × g_lum/2) of the binuclear complexes being among the highest reported to date for chiral iridium(III) complexes.

中文翻译：

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磷光手性阳离子双核铱 （III） 配合物：提高圆偏振发光亮度


我们报道了由对映体纯构建单元 [μ-Cl₂（Δ-Ir（C^N）₂）₂] 和 [μ-Cl₂（Λ-Ir（C^N）_2）2]制备的两种手性双核铱 （III） 配合物（ΛΛ 和 ΔΔ）的合成和表征。这些构建单元是通过中性铱 （III） 配合物 Irpiv （piv = 2,2,6,6-四甲基庚烷-3,5-二酸酯） 的手性制备高效液相色谱，然后选择性降解辅助配体获得的。为了进行比较，我们还合成了单体 （IrL¹） 和二聚体 （Ir₂L²，混合物）。所有复合物都表现出相似的发射特性，在光谱的橙红色区域发射，具有良好的光致发光量子产率（λ_max = 610–625 nm，Φ ∼ 25%，τ ∼ 800–900 ns）。然而，ΛΛ 和 ΔΔ 配合物具有光学活性，表明在不同的合成步骤中没有发生异构化，圆二色光谱及其圆偏振发光 （CPL） 都证明了这一点。二聚体（Ir₂L²、ΛΛ和ΔΔ）的资本增益是单体（IrL¹）的4倍亮度（B₃₈₀ =_{ε 380 nm} × Φ）和双核配合物的CPL亮度（B_CPL = B_{380 ×} g_lum/2）是迄今为止报道的最高手性铱（III）配合物之一。