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Updated: Feb 20, 2026

Author Spotlight: Functionalizing Metal-Organic Frameworks: Advancements, Challenges, and the Power of Post-Synthetic Ligand Exchange
Published on: June 23, 2023
A pH-Dependent, Mechanically Interlocked Switch: Organometallic [2]Rotaxane vs. Organic [3]Rotaxane
Philipp J Altmann1, Alexander Pöthig1
1Catalysis Research Center & Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer-Strasse 1, 85747, Garching, Germany.
Abstract:
We present the first [2]rotaxane featuring a functional organometallic host. In contrast to the known organic scaffolds, this assembly shows a high post-synthetic modifiability. The reactivity of the Ag8 pillarplex host is fully retained, as is exemplified by the first transmetalation in a rotaxane framework to provide the respective Au8 analogue. Additionally, a transformation under acidic conditions to give a purely organic [3]rotaxane is demonstrated which is reversible upon addition of a suitable base, rendering the assembly a pH-dependent switch. Hereby, it is shown that the mechanically interlocked nature of the system enhances the kinetic stability of the NHC host complex by a factor of >1000 and corresponds to the first observation of a stabilizing "rotaxand effect".
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