Conductive Two-Dimensional Supramolecular Polymers via Cation-π driven Self-Aligned Aromatic Brick-Like Stacking

Achieving molecular self-assembly to produce functional supramolecular polymers with defined dimensions and structural periodicity is crucial, particularly for two-dimensional supramolecular polymers (2DSPs). However, a major challenge to their application has been poor electrical conductivity due to weak π-electron delocalization in existing synthetic methods. Here, we overcome this limitation by demonstrating the controlled construction of conductive 2DSPs through self-aligned brick-like stacking of doubly charged π-conjugated monomers driven by aromatic cation-π interactions. A key feature of this approach is the upright molecular orientation, a notable departure from the horizontal orientation typical of conventional 2D polymers. This versatile method is compatible with various molecular building blocks, enabling modulation of 2DSP conformation from flat to wavy. We have also prepared free-standing single-layer nanosheets of 2DSPs via solution-assisted exfoliation from their crystals. The resulting 2DSPs demonstrate efficient in-plane π-electron delocalization, leading to impressive electrical conductivity properties, holding significant promise for optoelectronic applications.(Formula