Supramolecular Luminescent Gold(I)−Copper(I) Complexes: Self-Assembly of the Au_<i>x</i>Cu_<i>y</i> Clusters inside the [Au₃(diphosphine)₃]³⁺ Triangles

The reactions between diphosphino−alkynyl gold complexes (PhC2Au)PPh2(C6H4)nPPh2(AuC2Ph) (n = 1, 2, 3) with Cu+ lead to formation of the heterometallic aggregates, the composition of which may be described by a general formula [{AuxCuy(C2Ph)2x}Au3{PPh2(C6H4)nPPh2}3]3+(y−x) (n = 1, 2, 3; x = (n + 1)(n + 2)/2; y = n(n + 1)). These compounds display very similar structural patterns and consist of the [AuxCuy(C2Ph)2x]y−x alkynyl clusters “wrapped” in the [Au3(diphosphine)3]3+ triangles. The complex for n = 1 was characterized crystallographically and spectrally, the larger ones (n = 2, 3) were investigated in detail by NMR spectroscopy. Their luminescence behavior has been studied, and a remarkably efficient emission with a maximum quantum yield of 0.92 (n = 1) has been detected. Photophysical experiments demonstrate that an increase of the size of the aggregates leads to a decrease in photostability and photoefficiency. Computational studies have been performed to provide additional insight into the structural and electronic properties of these supramolecular complexes. The theoretical results obtained are in good agreement with the experimental data, supporting the proposed structural motif. These studies also suggest that the observed efficient long-wavelength luminescence originates from metal-centered transitions within the heterometallic Au−Cu core.二膦基-炔基金配合物（diphosphino−alkynyl gold complexes）(PhC₂Au)PPh₂(C₆H₄)ₙPPh₂(AuC₂Ph)（n=1、2、3）与一价铜离子（Cu⁺）发生反应，可生成异金属聚集体，其组成可用通式[{AuₓCuᵧ(C₂Ph)₂ₓ}Au₃{PPh₂(C₆H₄)ₙPPh₂}₃]³⁺(ʸ⁻ˣ) 描述（其中n=1、2、3；x=(n+1)(n+2)/2；y=n(n+1)）。这类化合物具有高度相似的结构特征，其结构由被[Au₃(双膦配体)₃]³⁺三角形笼状结构包裹的[AuₓCuᵧ(C₂Ph)₂ₓ]ʸ⁻ˣ炔基簇构成。n=1的配合物已通过单晶衍射与光谱学手段完成表征，而尺寸更大的n=2、3类聚集体则通过核磁共振波谱法（NMR spectroscopy）进行了详细研究。研究团队对这类聚集体的发光行为开展了探究，其中n=1的样品观测到了量子产率最大值达0.92的极高效率发射。光物理实验结果表明，聚集体尺寸增大时，其光稳定性与发光效率均会降低。本研究开展了计算化学研究，以进一步阐明这类超分子配合物（supramolecular complexes）的结构与电子性质；所得理论结果与实验数据高度吻合，佐证了所提出的结构基元。上述研究还表明，观测到的高效长波长发光源于异金属Au-Cu核内的金属中心跃迁。