Planet-satellite cage hybrids: covalent organic cages encircling metal organic cage

As a rising type of precisely molecular nanoobjects, porous molecular cages, including covalent organic cages (COCs) and metal organic cages (MOCs), have attracted much more attention. It is fascinating to construct well-defined cage hybrids combining COCs and MOCs to further rich their types, properties, and applications. However, it is a big challenge due to the isotropy of the porous molecular cages. In this article, an anisotropic COC ligand based on aryl ether bonds and bearing one isophthalate moiety has been designed and synthesized. Then planet-satellite cage hybrids (PSCHs), MOC@COCs, have been constructed through the coordination of the anisotropic COC ligand and copper ions with or without the help of extra dicarboxylic ligands in an almost quantitative manner for the first time. Three PSCHs with one different topological MOC (heteroleptic bipolar, distorted cuboctahedral or homoleptic cuboctahedral) as the planet and different numbers of COCs (6, 12 or 24) as satellites are obtained. The structural and thermal properties of these PSCHs have also been studied. The obtained PSCHs exhibit discrete, uniform and stable structures, good solubility and strong film-forming property.