The structural and photophysical properties of tetradentate Pt(ppzOppz), Pt(ppzOpopy), Pt(ppzOczpy), and Pt(czpyOczpy) have been experimentally and theoretically explored. Single-crystal diffraction measurements provided accurate structural information. Electrochemical and photophysical characterizations revealed internal electronic energy levels in ground and excited states. (Time-dependent) Density functional theory calculation revealed electron distributions in transition processes of S₀ → S₁ and S₁ → T₁ → S₀. Electronic transition study indicated that Pt(ppzOppz) demonstrated mixed MLCT/LC states and Pt(czpyOczpy) showed MLCT-dominated states in S₁ and T₁. Both Pt(ppzOpopy) and Pt(ppzOczpy) presented strong delocalized spin transition (DST) during intersystem crossing. Upon frame modification of Pt(ppzOczpy), we found that their S₁ and T₁ can be independently manipulated. These blue emitters showed a tunable and narrow emission band (the narrowest fwhm was 19 nm) with luminescence efficiency as high as 86%. The findings of the DST transition mode in the neutral Pt(II) complexes provide guidance for rational design of novel phosphorescent materials.

中文翻译：

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探测三重态激发态并管理中性四齿铂（II）配合物的蓝光发射

通过实验和理论研究了四齿Pt（ppzOppz），Pt（ppzOpopy），Pt（ppzOczpy）和Pt（czpyOczpy）的结构和光物理性质。单晶衍射测量提供了准确的结构信息。电化学和光物理特征揭示了基态和激发态的内部电子能级。（随时间变化）密度泛函理论计算显示出S ₀ →S ₁和S ₁ →T ₁ →S _0的跃迁过程中的电子分布。电子跃迁研究表明，Pt（ppzOppz）显示了混合的MLCT / LC状态，而Pt（czpyOczpy）显示了S ₁和T _1中的MLCT为主的状态。。在系统间穿越过程中，Pt（ppzOpopy）和Pt（ppzOczpy）都表现出很强的离域自旋跃迁（DST）。在对Pt（ppzOczpy）进行框架修改后，我们发现它们的S ₁和T ₁可以独立操纵。这些蓝色发射器显示出可调的窄发射带（最窄的fwhm为19 nm），发光效率高达86％。中性Pt（II）配合物中DST过渡模式的发现为新型磷光材料的合理设计提供了指导。