Work

Highly Selective Construction of Unique Cyclic [4]Catenanes Induced by Multiple Noncovalent Interactions

Year: 2024

Type: article

Abstract: The synthesis of high‐ordered mechanically interlocked supramolecular structures is an extremely challenging topic. Only two linear [4]catenanes have been reported so far and there is no defined strategy to obtain cyclic [4]catenane. Herein, two unprecedented cyclic [4]catenanes, 1 and 2, were prepared in high yields. The syntheses rely on the strategic selection of naphthalenediimide (NDI) based Cp*Rh/Ir building blocks E1/E2 (Cp*=pentamethyl‐cyclopentadienyl) and nonlinear diimidazole ligand precursor L1, exhibiting large conjugate plane, appropriate coordination angles, and freely rotating imidazole units, thereby enabling multiple π⋅⋅⋅π stacking interactions to maintain the supramolecular structures. The use of other Cp*Rh building blocks E3, E4 or E5 featuring slightly shorter metal‐to‐metal distances than E1/E2 and different chemical properties led to the formation of a complex 3 and two metallamacrocycles 4 or 5, respectively. The structures of these assemblies were confirmed by X‐ray crystallographic analysis, ESI‐TOF‐MS and NMR spectroscopy. Complex 1, exhibiting a broad‐band absorption in the UV/Vis to NIR regions and a remarkable photothermal conversion was thereafter used to build the new 1 membrane. The solar power‐induced water steam generation performance of 1 membrane was investigated, reaching a value of 2.37 kg ⋅ m−2 ⋅ h−1, making it suitable for collection of fresh water via desalination and wastewater.

Source: Angewandte Chemie

DOI: 10.1002/ange.202422444