Harnessing remote weak interactions for fine-tuning the catalytic activity of rotaxane-superbases
- 1Faculty of Chemistry (Organic Chemistry) and Center for Nanointegration Duisburg-Essen (CENIDE, University of Duisburg-Essen, Universitätsstrasse 7, Essen, Germany, 45141
Abstract
Mechanically interlocked molecules offer a distinct strategy for controlling molecular function by translating subtle differences in noncovalent interactions into changes in molecular conformation and reactivity. Here, we show that remote weak interactions can be harnessed to fine-tune the basicity and catalytic activity of mechanically interlocked secondary amines. To this end, we synthesized two bistable rotaxanes, featuring a primary ammonium/amine binding site and either a triazole or a methyltriazolium unit as the secondary binding site. In the base-catalysed Michael addition of malononitrile to beta-nitrostyrene, both deprotonated amine-rotaxanes exhibit substantially higher catalytic activity than both the corresponding non-interlocked thread and the benchmark organobase proton sponge, demonstrating that the mechanical bond can enhance the reactivity of the embedded amine. Importantly, the triazole based-rotaxane shows a twofold higher catalytic activity than that of the triazolium-rotaxane, although the secondary amine as the catalytically active unit is structurally unchanged. Thus, the increased reactivity is caused by the difference in weak noncovalent interactions at the secondary binding site: Weaker binding to the triazole translates into higher basicity of the secondary amine, which in turn increases the catalytic activity of the rotaxane. Collectively, these results demonstrate that weak, remote interactions transmitted through a mechanical bond can modulate the proton-accepting ability and catalytic performance of an interlocked amine, establishing remote co-conformational control of basicity as a design principle for fine-tuning the reactivity of rotaxane superbases.
Related
- Harnessing Nanozyme Catalytic Activities for Multi-Target Intervention in Neurodegenerative Pathology
- Harnessing phosphine oxide interactions with HF and HBF4 to enable the hydrofluorination of alkynes
- A Boomerang Catalyst Combining High Catalytic Activity and Reusability for Aqueous Transfer Hydrogenation of Ketones
- Beyond the catalytic serine: selective protease engagement with covalent macrocyclic activity-based probes
- Harnessing π-d magnetic interactions in Co porphyrins by metal-ligand coordination
BibTeX
@misc{kundu2026harnessing,
title = {{Harnessing remote weak interactions for fine-tuning the catalytic activity of rotaxane-superbases}},
author = {Sohom Kundu and Shubhadip Mallick and Shounak Hinge and Jan Riebe and Jochen Niemeyer},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010318/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010318/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Harnessing remote weak interactions for fine-tuning the catalytic activity of rotaxane-superbases
AU - Sohom Kundu
AU - Shubhadip Mallick
AU - Shounak Hinge
AU - Jan Riebe
AU - Jochen Niemeyer
PY - 2026
DA - 2026/10/12
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010318/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010318/v1
AB - Mechanically interlocked molecules offer a distinct strategy for controlling molecular function by translating subtle differences in noncovalent interactions into changes in molecular conformation and reactivity. Here, we show that remote weak interactions can be harnessed to fine-tune the basicity and catalytic activity of mechanically interlocked secondary amines. To this end, we synthesized two bistable rotaxanes, featuring a primary ammonium/amine binding site and either a triazole or a methyltriazolium unit as the secondary binding site. In the base-catalysed Michael addition of malononitrile to beta-nitrostyrene, both deprotonated amine-rotaxanes exhibit substantially higher catalytic activity than both the corresponding non-interlocked thread and the benchmark organobase proton sponge, demonstrating that the mechanical bond can enhance the reactivity of the embedded amine. Importantly, the triazole based-rotaxane shows a twofold higher catalytic activity than that of the triazolium-rotaxane, although the secondary amine as the catalytically active unit is structurally unchanged. Thus, the increased reactivity is caused by the difference in weak noncovalent interactions at the secondary binding site: Weaker binding to the triazole translates into higher basicity of the secondary amine, which in turn increases the catalytic activity of the rotaxane. Collectively, these results demonstrate that weak, remote interactions transmitted through a mechanical bond can modulate the proton-accepting ability and catalytic performance of an interlocked amine, establishing remote co-conformational control of basicity as a design principle for fine-tuning the reactivity of rotaxane superbases.
ER -