iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
A 2024 study showed that chemists can remove a nitrogen atom from a rotaxane axle and replace it with a carbon–carbon bond while preserving the molecule’s mechanical link. The method uses an anomeric amide to activate a secondary amine, but the reported yields were modest and the reaction depends on the ring’s position and the axle fragments recombining before the ring slips off.
What nitrogen deletion changes in a rotaxane
A rotaxane consists of a molecular ring threaded over a linear component called an axle. Bulky groups, or stoppers, at the axle’s ends prevent the ring from sliding off. The ring and axle are not joined by an ordinary covalent bond; they are held together by their mechanical interlocking.
In the 2024 study, the axle contained a dibenzylammonium site. That nitrogen-containing site had helped template the assembly of the interlocked molecule, and it was also the part the chemists removed. The remaining axle fragments formed a new carbon–carbon bond, leaving the macrocycle threaded on the axle. The authors describe the transformation as one in which “a carbon–carbon bond … replaces the amine nitrogen.” Gauthier et al., Journal of the American Chemical Society (published online October 21, 2024).
How the 2024 reaction works
The proposed mechanism is a sequence of chemical steps, not simply a nitrogen atom being plucked out of an intact axle. The ring’s position and the timing of bond formation matter because the axle temporarily separates into reactive fragments.
#1 Best Overall
- Visualize Molecular: The molecular model kit simplifies complex chemistry concepts into tangible 3D structures improve learning efficiency, suitable for students from Grade 7 to Graduate level.
- 240 Pcs Complete Set: The atom model kit includes with 86 atoms and 154 bonds, explore most the molecules structures from simple compounds to complex polymers.
- Effortless Assembly: Embedded component design ensures easy to construct Ball-and-stick and Space-filling models that maximizes focus on exploration without complex assembly.
- Durable & Portable: Built to last, the chemistry set is crafted from high-quality materials. Plus, its portable design allows you to take your experiments learning anywhere, between the home, classroom and lab.
- Essential Study Tool: Whether you're studying organic chemistry, biochemistry, or molecular biology, molecule building kit is an perfect learning tool for you deeper comprehension of molecular science.
- Deprotonation: The ammonium/amine site is deprotonated, allowing the macrocycle to move away from the reactive site.
- Amine activation: An anomeric amide reagent activates the secondary amine.
- Nitrogen extrusion: The proposed pathway forms an isodiazene intermediate, which releases molecular nitrogen and leaves a diradical pair.
- Axle reconnection: The radical fragments recombine to form the carbon–carbon bond that replaces the nitrogen-containing site.
This mechanism creates a race: the radicals must recombine before the macrocycle dethreads or the fragments escape from the solvent cage. The open-access paper discusses how the accessible ring coconformations can either leave the amine available for reaction or obstruct it. Full text of the 2024 study.
What the first study demonstrated—and what it did not
Gauthier and colleagues reported nitrogen deletion across a series of crown ether–dibenzylammonium rotaxanes, with isolated product yields of 23–36%. Those are yields for the specific laboratory reactions reported, not a general success rate for rotaxanes or a measure of commercial readiness. The products were characterized using NMR spectroscopy, mass spectrometry, and X-ray crystallography. 2024 study.
Rank #2
- Visualize Molecular: The molecular model kit simplifies complex chemistry concepts into tangible 3D structures improve learning efficiency, suitable for students from Grade 7 to Graduate level.
- 444 Pcs Complete Set: The atom model kit includes with 136 atoms,158 bonds, and 150 fullerene model parts, explore most the molecules structures from simple compounds to complex polymers.
- Effortless Assembly: Embedded component design ensures easy to construct Ball-and-stick and Space-filling models that maximizes focus on exploration without complex assembly.
- Durable & Portable: Built to last, the chemistry set is crafted from high-quality materials. Plus, its portable Snap-Lock design allows you to take your experiments learning anywhere, between the home, classroom and lab.
- Essential Study Tool: Whether you're studying organic chemistry, biochemistry, or molecular biology, molecule building kit is an perfect learning tool for you deeper comprehension of molecular science.
The result establishes a way to alter the axle’s connectivity while retaining the mechanical bond in the studied examples. It does not establish that the method works for every rotaxane, ring, or axle. The authors’ reported scope depends on whether the macrocycle can adopt coconformations that do not prevent reaction at the amine.
In the solid-state structure of one product, weak CH···O interactions linked crown ether oxygen atoms with benzylic methylene groups. In that observed crystal structure, these interactions took the place of the parent molecule’s ammonium-based binding motif. This is a finding about one crystallographic structure, not evidence that all products behave this way in solution.
Rank #3
![[239 PCS] Organic Chemistry Model Kit | Molecular Model Kit for Students](https://m.media-amazon.com/images/I/511A7UN+wEL._SL160_.jpg)
- 𝐇𝐀𝐍𝐃𝐒-𝐎𝐍 𝐂𝐇𝐄𝐌𝐈𝐒𝐓𝐑𝐘 𝐋𝐄𝐀𝐑𝐍𝐈𝐍𝐆: Take chemistry beyond memorizing formulas with an interactive learning experience students can physically handle. Manipulating the pieces of this molecule kit gives learners a more engaging way to practice identifying atoms, connecting bonds, and studying molecular structures.
- 𝐓𝐔𝐑𝐍 𝟐𝐃 𝐃𝐈𝐀𝐆𝐑𝐀𝐌𝐒 𝐈𝐍𝐓𝐎 𝟑𝐃 𝐌𝐎𝐃𝐄𝐋𝐒: Make textbook structures easier to interpret by transforming flat molecular diagrams into physical 3D models. With the help of this chemistry modeling kit students can see the position of atoms and bonds from different angles, helping them better understand molecular shape and arrangement.
- 𝐁𝐔𝐈𝐋𝐃, 𝐄𝐗𝐏𝐋𝐎𝐑𝐄 & 𝐑𝐄𝐁𝐔𝐈𝐋𝐃: Encourage active discovery by letting students construct a structure, adjust its arrangement, and build it again for continued practice. The reusable pieces make it easy to explore different molecular configurations without needing a new model for every lesson.
- 𝐄𝐅𝐅𝐎𝐑𝐓𝐋𝐄𝐒𝐒 𝐀𝐒𝐒𝐄𝐌𝐁𝐋𝐘: Designed for smooth, straightforward model building, the pieces connect easily so students can spend less time figuring out how to assemble the kit and more time exploring chemistry. Simple construction also makes it convenient for repeated classroom or study use.
- 𝐆𝐈𝐕𝐄 𝐓𝐇𝐄 𝐆𝐈𝐅𝐓 𝐎𝐅 𝐃𝐈𝐒𝐂𝐎𝐕𝐄𝐑𝐘: Bring a creative twist to science gifting with this organic chemistry molecular model kit made for curious students, chemistry fans, and STEM enthusiasts. Whether for a birthday, classroom reward, holiday, or special occasion, it gives recipients something interesting to build, examine, and enjoy.
How the 2025 follow-up differs
A separate 2025 study extended nitrogen deletion to multiple template sites in rotaxanes, catenanes, and a molecular knot, using O-diphenylphosphinylhydroxylamine (DPPH). The authors reported rotaxane deletion yields up to 51% and found that only one secondary-amine substituent needed to be radical-stabilizing. The examples below are specific reactions, not directly comparable performance tests against the 2024 work: the substrates and procedures differ.
| 2025 example | Reported transformation | Yield |
|---|---|---|
| Doubly threaded [3]rotaxane | Deletion at two template sites | 37% |
| [3]catenane | Deletion at two template sites | 45% |
| [2]catenane | Four nitrogen deletions from both rings | 33% |
| Molecular trefoil knot | Six nitrogen deletions | 7% |
Repeated deletion poses additional mechanical challenges: a linked architecture must remain intact while its molecular components are altered. In a catenane or knot, unlinking or uncrossing can be a concern alongside the dethreading risk in rotaxanes. The 2025 findings therefore broaden the kinds of interlocked structures in which deletion was demonstrated; they do not change the reagent, yields, or results reported for the 2024 anomeric-amide study. Couto et al., Journal of the American Chemical Society (published online August 28, 2025).
Rank #4
- FOR BASIC TEACHING TO ADVANCED SCIENCE: 444 pieces molecular model kit, including 136 atoms, 158 bonds and 150 parts for Carbon-60(Fullerene), provides to students from Grade 7 to Graduate level.
- TWO CHEMICAL STRUCTURE MODELS: The ball-and-stick models use spheres to represent atoms and sticks to represent chemical bonds. In the space-filling model, the spheres are drawn to scale and are next to one another as atoms are in real molecules.
- CHEMISTRY EDUCATIONAL MOLECULE MODEL IN 3D: It can display chemical structure, molecular bond, and bond angle in all directions. Demonstrate fundamental molecular geometry, chemical molecular structure, stereochemistry with 3D modeling studies.
- EASY TO LEARN: The universal standard adopted for each atom's color makes it easier for you to use and learn. Atoms and chemical bonds combine tightly and firmly and can be easily disassembled by disconnecting tools.
- If you’re not in love with it for whatever reason, we’ll give you a full replacement or refund—no questions asked. If you have any doubt, please tell us. With nothing to worry about, or even to share with your friends, try it now.
Why the result matters
The work is an example of skeletal editing: changing the atoms and bonds within a molecule’s framework rather than merely adding a group to its surface. Here, nitrogen served first as part of a template site and was later removed as the axle was reconnected with a carbon–carbon bond. Doing that while preserving a mechanical interlock makes the reaction a demonstration of molecular architecture as well as bond-forming chemistry. The studies are specialist laboratory research, not consumer procedures.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →Quick Recap
Best Value
![[118 PCS] Organic Chemistry Model Kit | Molecular Model Kit for Students](https://m.media-amazon.com/images/I/41sdPAEl5gL._SL160_.jpg)
- 𝐇𝐀𝐍𝐃𝐒-𝐎𝐍 𝐂𝐇𝐄𝐌𝐈𝐒𝐓𝐑𝐘 𝐋𝐄𝐀𝐑𝐍𝐈𝐍𝐆: Take chemistry beyond memorizing formulas with an interactive learning experience students can physically handle. Manipulating the pieces of this molecule kit gives learners a more engaging way to practice identifying atoms, connecting bonds, and studying molecular structures.
- 𝐓𝐔𝐑𝐍 𝟐𝐃 𝐃𝐈𝐀𝐆𝐑𝐀𝐌𝐒 𝐈𝐍𝐓𝐎 𝟑𝐃 𝐌𝐎𝐃𝐄𝐋𝐒: Make textbook structures easier to interpret by transforming flat molecular diagrams into physical 3D models. With the help of this chemistry modeling kit students can see the position of atoms and bonds from different angles, helping them better understand molecular shape and arrangement.
- 𝐁𝐔𝐈𝐋𝐃, 𝐄𝐗𝐏𝐋𝐎𝐑𝐄 & 𝐑𝐄𝐁𝐔𝐈𝐋𝐃: Encourage active discovery by letting students construct a structure, adjust its arrangement, and build it again for continued practice. The reusable pieces make it easy to explore different molecular configurations without needing a new model for every lesson.
- 𝐄𝐅𝐅𝐎𝐑𝐓𝐋𝐄𝐒𝐒 𝐀𝐒𝐒𝐄𝐌𝐁𝐋𝐘: Old nobby molecular kit is designed for smooth, straightforward model building, the pieces connect easily so students can spend less time figuring out how to assemble the kit and more time exploring chemistry. Simple construction also makes it convenient for repeated classroom or study use.
- 𝐆𝐈𝐕𝐄 𝐓𝐇𝐄 𝐆𝐈𝐅𝐓 𝐎𝐅 𝐃𝐈𝐒𝐂𝐎𝐕𝐄𝐑𝐘: Bring a creative twist to science gifting with this organic chemistry molecular model kit made for curious students, chemistry fans, and STEM enthusiasts. Whether for a birthday, classroom reward, holiday, or special occasion, it gives recipients something interesting to build, examine, and enjoy.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
