The cationic Pt complexes with amide groups have been found to show dimer emission through hydrogen bonding interactions with counter anions even at low concentration. In order to investigate further details of dimer emission, we prepared three Pt complexes, Pt·B(C₆F₅)₄, Pt·Cl, and Pt·PF₆, whose counter anions possess different strengths of a hydrogen bonding acceptor. Hydrogen bonding interactions in the ground state and excited-state dynamics of the Pt complexes were evaluated by NMR analysis, temperature dependence, and kinetics of dimer emission. These studies revealed that the hydrogen bonding interaction in the ground state is essential for dimer emission, but too strong hydrogen bonding prevents dimer emission due to the inhibition of a stacked dimer formation in the excited state. Owing to this trade-off, the Pt complex with a moderate hydrogen bonding acceptor, PF₆⁻, most effectively shows dimer emission. In general, a strong supramolecular interaction efficiently provides a desired assembled structure showing multi-molecular emission. We revealed a unique phenomenon that a moderate interaction is beneficial to effective multi-molecular emission.

中文翻译：

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通过氢键相互作用 的阳离子Pt（ii）配合物的多分子发射†

已发现具有酰胺基的阳离子Pt配合物即使在低浓度下也能通过与抗衡阴离子的氢键相互作用而显示出二聚体发射。为了研究二聚体发射的更多细节，我们制备了三种Pt配合物Pt·B（C ₆ F ₅）₄，Pt·Cl和Pt·PF ₆，其抗衡阴离子具有氢键键合受体的不同强度。Pt配合物的基态和激发态动力学中的氢键相互作用通过NMR分析，温度依赖性和二聚体发射动力学进行了评估。这些研究表明，基态的氢键相互作用对于二聚体发射是必不可少的，但是太强的氢键由于抑制了激发态下堆积的二聚体的形成而阻止了二聚体的发射。由于这种折衷，所述Pt络合物具有中等的氢键受体，PF ₆ ^-，最有效地显示了二聚体发射。通常，强的超分子相互作用有效地提供了显示多分子发射的所需组装结构。我们揭示了一个独特的现象，适度的相互作用有利于有效的多分子发射。