What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
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
In 2019, chemists reported catenanes and a trefoil knot built from para-connected benzene rings. The isolated structures contain only carbon and hydrogen; they do not form spontaneously, but are made through a deliberately designed synthetic route. The work showed that ring-shaped molecules made from these units can be mechanically interlocked and knotted, and that the knot remains dynamic in solution even at very low temperature.
What the chemists made
The study by Yasutomo Segawa, Kenichiro Itami and coauthors reported two kinds of molecular architecture: catenanes, in which closed rings pass through one another, and a molecular trefoil knot. In each, the building units are benzene rings connected at their para positions. The resulting structures are composed solely of carbon and hydrogen, unlike many mechanically interlocked molecules that incorporate heteroatoms.
“Just benzene rings” describes the composition and arrangement of the final structures, not a simple self-assembly of ordinary benzene molecules. The researchers designed and carried out a synthetic route to create the required connectivity.
Free tools Windows power users keep installed
One-click scans. No signup required.
How a molecular knot differs from an interlocked pair of rings
Catenanes: rings linked through one another
A catenane consists of two or more closed molecular rings that are mechanically linked. The rings are not joined by an ordinary chemical bond at the crossing; their closed paths prevent them from separating without a bond being broken or a ring being opened.
#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.
Trefoil knot: one continuous closed path
A trefoil knot is a single molecular loop whose path crosses over and under itself in the familiar three-crossing knot pattern. Unlike a catenane, it is not two separate rings linked together. In both cases, the defining feature is the topology of the connected molecular path, not merely how a flat drawing happens to look.
How a carbon-and-hydrogen structure could be synthesized
The final knot contains only carbon and hydrogen, but that does not mean every intermediate in its preparation had the same composition. A 2022 review describes a strategy that uses silicon bridges during synthesis, including a macrocyclic precursor with two silicon bridges for the [24]CPP trefoil knot. Those temporary bridges help guide construction; their use in a precursor is compatible with the isolated target being an all-carbon-and-hydrogen structure.
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 available primary record is the 2019 paper’s abstract, rather than its full experimental text. It establishes the reported structures and selected properties, but does not provide exact reaction conditions, yields or complete characterization details. The reported result should therefore not be mistaken for a practical step-by-step synthesis recipe.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsWhy the trefoil knot is chiral
The all-benzene knot is topologically chiral: its two possible handed forms cannot be made identical simply by rotating or turning the molecule over. The authors confirmed the handedness through enantiomer separation and circular dichroism spectroscopy. This chirality arises from the knot’s three-dimensional connectivity, rather than requiring an asymmetric atom such as a carbon attached to four different groups.
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.
The knot moved in solution, even at −95 °C
Despite its apparently rigid structure, the trefoil knot showed rapid vortex-like motion in solution at temperatures down to −95 °C. The authors reported that this movement produced averaged nuclear magnetic resonance signals for all the hydrogen atoms. In other words, the measured signals reflected motion that was fast on the timescale of the NMR observation, rather than each hydrogen appearing as a permanently distinct, stationary environment.
This is evidence of molecular motion under the reported solution conditions, not evidence that the knot is a useful motor or that it has been demonstrated in a device. The paper presented the behavior as a reason to investigate the structures further.
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.
What later work adds—and what it does not
A 2022 review placed these molecules in the wider context of nonplanar aromatic hydrocarbons and discussed their synthesis, chirality and dynamics. In 2025, Yang and coauthors published first-principles calculations of the linear and nonlinear optical spectra of all-benzene catenane and trefoil structures. Those spectra are computational results; they do not by themselves demonstrate an optical application or a working device.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Why the result matters
The discovery demonstrated that a molecular knot and mechanically linked rings can be constructed from para-connected benzene units while leaving the isolated structures with carbon-and-hydrogen-only compositions. It also combined topology with measurable molecular behavior: the knot has distinguishable handed forms and moves rapidly in solution. The significance is a demonstration of what deliberate molecular design can build, not a claim that everyday benzene spontaneously forms knots or that the structures are already practical technologies.
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.
Sources
- Segawa et al., 2019, Science paper abstract indexed by PubMed (DOI: 10.1126/science.aav5021).
- 2022 review of nonplanar aromatic hydrocarbons.
- Yang et al., 2025, first-principles calculations of optical spectra.
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.
