Construction of an unprecedented 4 × 4-type Al16 molecular ring via ferrocene dicarboxylates.

Herein, we utilized flexible 4-coordinated ferrocene dicarboxylates to achieve a larger Al4 subunit and successfully constructed an Al16 molecular ring with an unprecedented 4 × 4 type structure. Single-crystal X-ray diffraction reveals that its abundant multi-atom synergy stems from its higher nuclearity. Together with ferrocene functionalization, its third-order non-linear optical performance is greatly enhanced.