Assembly of strongly phosphorescent hetero-bimetallic and -trimetallic [2]catenane structures based on a coinage metal alkynyl system

Homo-metallic metal alkynyl complexes exhibit interesting catenane structures, but their hetero-metallic catenane counterparts are under-developed. In this work, we report rare examples of bimetallic Au–Cu (DtbpC[triple bond, length as m-dash]C(–) ligand; Dtbp = 3,5-di-tert-butylphenyl), Au–Ag ((t)BuC[triple bond, length as m-dash]C(–) ligand), and Au–Cu, Au–Ag (C6-FluoC[triple bond, length as m-dash]C(–) ligand; C6-Fluo = 9,9-dihexyl-9H-fluoren-2-yl) complexes as well as a trimetallic Au–Ag–Cu (C6-FluoC[triple bond, length as m-dash]C(–) ligand) complex, which feature [2]catenane structures. The formation of the [2]catenane structure is significantly affected by the coinage metal ion(s) and change of the structure of the alkynyl ligand. These hetero-metallic [2]catenane structures are strongly luminescent with tunable emission λ(max) from 503 to 595 nm and Φ values up to 0.83.