Donor-Acceptor [2]- and [3]Catenanes Assembled from Versatile Pre-Organized Cp*Rh/Ir-Directed Pseudorotaxane Tectons.

A stepwise self-assembly protocol has been used to synthesize [2]- and [3]catenanes. Firstly, binuclear Cp*Rh/Ir-directed (Cp*=pentamethylcyclopentadienyl) pseudorotaxanes were prepared through self-assembly, driven by donor-acceptor interactions between electron-deficient naphthalenediimide (NDI) units and an electron-rich crown ether. Subsequently, the pre-organized pseudorotaxanes were applied as tectons for self-assembly of [2]- and [3]catenanes by combination with very simple linkers. The structures of the catenanes were confirmed by NMR spectroscopy, ESI mass spectrometry, single-crystal X-ray diffraction analysis, and elemental analysis.