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Rotational Control of a Dirhodium-Centered Supramolecular Four-Gear System by Ligand Exchange
Kazuma Sanada1, Hitoshi Ube1, Mitsuhiko Shionoya1
1Department of Chemistry, Graduate School of Science, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-003, Japan.
Abstract:
Self-assembled molecular machines have great potential to enable noncovalent regulation of a coupled motion of the building blocks. Herein we report the synthesis and the rotational control of a lantern-type dirhodium complex with circularly arranged four 2,3,6,7,14,15-hexamethyltriptycene carboxylates as gears and two axial ligands as the rate control elements. The rotating rates in solution were markedly affected by the coordination ability and the bulkiness of axial ligands. Notably, the rate changes were closely correlated with the changes in the electronic states of the dirhodium center. Such ligand exchange-based control of rotational motions with color changes would advance stimulus-responsive metallo-molecular multirotors.
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