Precise synthesis of π-conjugated [3]catenanes and Solomon link for photothermal responses via a dual-tuning strategy

Mechanically interlocked supramolecular compounds have garnered widespread attention but it remains challenging to investigate topological adjustments in such complicated structures. Here, the authors use a bidentate pyridyl ligand featuring an extended π-conjugated plane for coordination-directed self-assembly to engineer three different kinds of sophisticated complexes, including three Linear [3]catenanes 1(OTf)12, 2(OTf)12 and 3(OTf)12, two Borromean rings 4(OTf)12 and 5(OTf)12, and one heterometallic Solomon link 6(OTf)8 by modulating the Ru···Ru distances and conjugation planes of the building units or incorporating bridging silver ions. Subtle alterations in the building units can yield a diversity of topological architectures. Differences in the photothermal conversion properties of 1(OTf)12 − 6(OTf)8 are investigated. Various photothermal conversion efficiencies (23% − 81%) are obtained because of the synergistic effect of π···π stacking interactions and the free radical effect of building units. This finding enables the precise regulation of topology, thereby leading to a remarkable enhancement in photothermal conversion efficiency. Mechanically interlocked supramolecular compounds have garnered widespread attention but it remains challenging to investigate topological adjustments in such complicated structures. Here, the authors use a bidentate pyridyl ligand featuring an extended π-conjugated plane for coordination-directed self-assembly to engineer three different kinds of sophisticated complexes.