Photoluminescent gold clusters are functionally variable chemical modules by ligand design. Chemical modification of protective ligands and introduction of different metals into the gold clusters lead to discover unique chemical and physical properties based on their significantly perturbed electronic structures. Here we report the synthesis of carbon-centered Au(I)-Ag(I) clusters with high phosphorescence quantum yields using N-heterocyclic carbene ligands. Specifically, a heterometallic cluster [(C)(Au^I-L)₆Ag^I₂]⁴⁺, where L denotes benzimidazolylidene-based carbene ligands featuring N-pyridyl substituents, shows a significantly high phosphorescence quantum yield (Φ = 0.88). Theoretical calculations suggest that the carbene ligands accelerate the radiative decay by affecting the spin-orbit coupling, and the benzimidazolylidene ligands further suppress the non-radiative pathway. Furthermore, these clusters with carbene ligands are taken up into cells, emit phosphorescence and translocate to a particular organelle. Such well-defined, highly phosphorescent C-centered Au(I)-Ag(I) clusters will enable ligand-specific, organelle-selective phosphorescence imaging and dynamic analysis of molecular distribution and translocation pathways in cells.

通过配体设计，光致发光金簇是功能可变的化学模块。保护性配体的化学修饰和将不同金属引入金簇导致发现基于其显着扰动的电子结构的独特化学和物理性质。在这里，我们报告了使用N-杂环卡宾配体合成具有高磷光量子产率的碳中心 Au(I)-Ag(I) 簇。具体来说，异金属簇 [(C)(Au ^I -L) ₆ Ag ^I ₂ ] ⁴⁺，其中 L 表示基于苯并咪唑亚基的卡宾配体，具有N-吡啶基取代基，显示出显着高的磷光量子产率 (Φ =  0.88）。理论计算表明，卡宾配体通过影响自旋轨道耦合加速了辐射衰变，而苯并咪唑亚基配体进一步抑制了非辐射途径。此外，这些具有卡宾配体的簇被吸收到细胞中，发出磷光并转移到特定的细胞器。这种明确的、高度磷光的 C 中心 Au(I)-Ag(I) 簇将实现配体特异性、细胞器选择性磷光成像以及细胞中分子分布和易位途径的动态分析。