Guest-Induced Helical Superstructure from a Gold Nanocluster-Based Supramolecular Organic Framework Enables Efficient Catalysis
Qiang Li, Wenxing Gao, Zijian Wang, Wenfeng Liu, Yu Fu, Xin Wang, Lili Tan, Li Shang, Ying‐Wei Yang
Abstract
Mimicking hierarchical assembly in nature to exploit atomically precise artificial systems with complex structures and versatile functions remains a long-standing challenge. Herein, we report two single-crystal supramolecular organic frameworks (MSOF-4 and MSOF-5) based on custom-designed atomically precise gold nanoclusters Au 11 (4-Mpy) 3 (PPh 3 ) 7, showing distinct and intriguing host–guest adaptation behaviors toward 1-/2-bromopropane (BPR) isomers. MSOF-4 exhibits sev topology and cylindrical channels with 4-mercaptopyridine (4-Mpy) ligands matching well with guest 1-BPR. Due to the confinement effect, solid MSOF-4 undergoes significant structural change upon selective adsorption of 1-BPR vapor over 2-BPR, resulting in strong near-infrared fluorescence. Single-crystal X-ray diffraction reveals that Au 11 (4-Mpy) 3 (PPh 3 ) 7 in MSOF-4 transforms into Au 11 Br 3 (PPh 3 ) 7 upon ligand exchange with 1-BPR, resulting in 1-BPR@MSOF-6 single crystals with a rarely reported helical assembly structure. Significantly, the double-helical structure of MSOF-6 facilitates efficient catalysis of the electron transfer (ET) reaction, resulting in a nearly 6 times increase of catalytic rates compared with MSOF-4. In sharp contrast, solid MSOF-5 possesses chb topology and cage-type channels with narrow windows, showing excellent selective physical adsorption toward 1-BPR vapor but a nonfluorescent feature upon guest adsorption. Our results demonstrate a powerful strategy for developing advanced assemblies with high-order complexity and engineering their functions in atomic precision.