Shape-Controlled Synthesis of Organometallic Microcrystal-Based Hollow Hexagonal Micromotors through Evaporation-Induced Supramolecular Self-Assembly

A facile strategy was developed to fabricate structure controllable microcrystals of ferrocene-based metal–organic (Fc-Ala-BCB) materials through evaporation-induced self-assembly. Two distinctive microcrystals, microrods and microtubes had been achieved by tuning the solvents during the self-assemblies. X-ray diffraction analysis was conducted on single crystals to investigate the packing mode of Fc-Ala-BCB molecules, which indicated the two crystals with the hexagonal system. Inheriting the aromaticity and chirality of ferrocenyl and l-Ala, this organic molecule self-assembled into a single-helix structure through intermolecule hydrogen bonds and π–π stacking. Theoretical analysis and stimulated computations were carried out to compare the surface energies of certain planes. Among those microcrystals, the microrods exhibited a higher chemical activity in catalyzing the decomposition of H<sub>2</sub>O<sub>2</sub>, due to the high-density atomic steps and kinks on the high energy surfaces. However, the hollow hexagonal tubes displayed appropriate catalytic activity and novel maneuverability toward catalyzing H<sub>2</sub>O<sub>2</sub>. The O<sub>2</sub> bubbles accumulated at the inner walls of the microtube were periodically released as individual bubbles, suggesting their potential application as a new kind of microengine (e.g., the microrotor).