Dave Leigh
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profdaveleigh.bsky.social
Dave Leigh
@profdaveleigh.bsky.social
Royal Society Research Professor & Sir Samuel Hall Chair of Chemistry, University of Manchester, UK. European. molecules・ machines・ magic
September 19, 2025 at 5:13 PM
Drs Clare Megarity & Jack Rowbotham😃
September 19, 2025 at 5:13 PM
...Yet here in @jacs.acspublications.org Daniel, Qi, Jess & co show they can delete multiple template sites from rotaxanes, catenanes and a molecular knot, severing the strands multiple times, and still end up with mechanically interlocked molecules. Amazing!🤯 pubs.acs.org/doi/10.1021/...
Multiple Template Site Nitrogen Atom Deletions from Rotaxanes, Catenanes, and a Molecular Knot
We report the deletion of nitrogen atoms from multiple template sites in rotaxanes, catenanes, and a molecular knot. Nitrogen extrusion from secondary amines in the backbone of the interlocked structures is achieved using O-diphenylphosphinylhydroxylamine (DPPH), forming carbon–carbon bonds while largely maintaining the integrity of the original mechanical bonding. We find that DPPH gives improved yields (up to 51%) for nitrogen atom deletions from template sites in rotaxanes compared to an anomeric amide nitrogen-deletion reagent and overcomes a major substrate limitation in that, using DPPH, only one of the substituents of the secondary amine in the rotaxane axle needs to be radical-stabilizing. Multiple template site nitrogen atom deletions were accomplished from a range of mechanically interlocked architectures, despite the potential for dethreading, unlinking, and/or strand uncrossing during each successive deletion event. Highlights include the deletion of two template sites from a doubly threaded [3]rotaxane (37% yield) and [3]catenane (45%), quadruple N-deletion of amines from both rings of a [2]catenane (33%), and six N-deletions from the six amine groups in a molecular trefoil knot (7%). The combination of skeletal editing with template synthesis provides a general strategy for synthesis that significantly increases the structural diversity of interlocked molecules that are potentially accessible.
pubs.acs.org
August 29, 2025 at 10:55 AM
In Macclesfield?😲
August 21, 2025 at 11:11 AM
I did not know that, Peggy 😃 The sales person at Harrods told us that the products have a very loyal customer base, lots of repeat business.
July 12, 2025 at 7:21 AM
Sadly it was only British cheeses, but a very nice Isle of Mull cheddar do that was fine 🧀
July 9, 2025 at 5:02 PM
Probably shooting up in the toilets 🤷‍♂️
July 9, 2025 at 4:58 PM
Novak up a break but down a set 😱 The Queen looking on….
July 9, 2025 at 4:51 PM
Jam on cream obvs 😋
July 9, 2025 at 3:58 PM
Comtes for us. Happy Father’s Day!🥂
June 15, 2025 at 10:15 PM
Well it’s not a knot but as far as I know it’s a new topology. It’s like cyclising the thread of a daisy chain back onto the macrocycle it’s attached to.
June 10, 2025 at 8:23 PM