异核双金属探针在活细胞细胞核和线粒体中选择性定位DNA

用于实时成像活细胞DNA的细胞核探针是非常罕见的。通过Ru(N^N)₃、Ir(C^N)₂(N^N)、Re(CO)₃Cl(N^N)和Pt(C^N)(N^N)的结合，生成了4种异核双金属配合物：2种不同的功能金属位点被锚定在线性双齿螯和配体(N^N)-(N^N)的尾端，形成不对称哑铃状的双金属分子M₁-M₂，即Ru-Re、Ru-Pt、Ir-Re和Ir-Pt。Ru-Re和Ru-Pt的红色发射探针具有较大的斯托克斯位移、优异的核膜穿透能力、良好光稳定性的DNA结合能力。此外，Ru-Re和Ru-Pt探针的DNA成像可与专门用于活细胞细胞核DNA染色的Hoechst 33342商用染料相媲美，而Ir-Re和Ir-Pt探针直接靶向线粒体。不同探针的发光特性和选择性胞内定位高度依赖于在异核双金属配合物中的金属物种。

Luminescent heterobimetallic probes for selectively locating DNA in the nucleus and mitochondria of live cells

Nucleus probes for real-time imaging of DNA in live cells are very rare. Herein, the combined use of Ru(N^N)₃, Ir(C^N)₂(N^N), Re(CO)₃Cl(N^N), and Pt(C^N)(N^N) produced four heterobimetallic complexes. Two different functional metal sites are arranged at both ends of linear bis-chelating linkers (N^N)-(N^N), leading to asymmetric dumbbell-like molecules M₁-M₂, namely, Ru-Re, Ru-Pt, Ir-Re, and Ir-Pt. The red emissive probes of Ru-Re and Ru-Pt offer the benefits of large Stokes shift, excellent nucleus membrane penetration, and DNA binding ability with good photostability. Moreover, DNA imaging of Ru-Re and Ru-Pt probes was comparable to the commercial dye of Hoechst 33342 which is specially used for staining DNA in the nucleus of live cells. However, the Ir-based probes of Ir-Re and Ir-Pt directly targeted mitochondria. The emission properties and selective intracellular localizations of different probes are highly dependent on the metal species used in the heterobimetallic complexes.