A team of chemists from the Chinese Academy of Sciences' Dalian Institute of Chemical Physics and a researcher from the University of Western Ontario have made a groundbreaking discovery: the world's smallest molecular knot (via Phys.org).
This accidental discovery, published in the prestigious journal Nature Communications, reveals a tightly-knotted structure made up of only 54 atoms.
Accidental Discovery
The researchers, comprising Zhiwen Li, Jingjing Zhang, Gao Li, and Richard Puddephatt, were initially focused on creating metal acetylides for organic reactions.
They aimed to connect carbon structures to gold acetylides, anticipating the formation of simple gold chains called caternames.
However, the outcome of one particular reaction surpassed their expectations, resulting in a self-assembled trefoil knot with no loose ends - a feat that occurred purely by accident.
"We've made many combinations of gold acetylides and phosphine ligands and they've never before given a trefoil knot. We hadn't predicted that this would happen in this case, so it was serendipity," research team head Richard Puddephatt tells NewScientist.
The Record-Breaking Trefoil Knot
This molecular trefoil metallaknot, labeled Au6, has a backbone crossing ratio (BCR) of 23, making it the smallest and tightest knot of its kind ever recorded.
Surpassing a previous record held by another Chinese team in 2020, which intentionally created a 69-atom knot, this new record-holder has left scientists perplexed due to its self-assembled nature.
The research team remains uncertain about the mechanisms behind this unintended formation, raising questions about the possibilities of creating even smaller knots.
The Knot's Significance
Beyond being a captivating laboratory discovery, the creation of such microscopic knots holds immense value in understanding natural occurrences.
In living organisms, knots made of DNA, RNA, and proteins play vital roles, and this accidental knot provides an intriguing glimpse into the intricacies of molecular structures.
The implications extend to materials science, offering potential insights into developing new polymers and plastics.
Scientific Challenges and Applications
Creating molecular knots is a challenging feat. The synthesis process involves meticulous design, often with the assistance of metal ions, to coax molecules into forming the desired knot.
The simplicity of the trefoil knot, coupled with its tight structure, makes it a fascinating subject for researchers. The accidental creation of Au6 opens new avenues for studying the self-assembly of molecular knots, challenging scientists to understand and replicate this process intentionally.
In Other News
A team of Chinese scientists from Guangzhou University's School of Materials Science and Engineering has developed a new porous ceramic with unprecedented strength and insulation properties, which has the potential to reshape the future of aerospace technology.
This high-entropy diboride ceramic, called 9PHEB, offers a balance of mechanical robustness and thermal insulation, making it an ideal candidate for hypersonic aircraft applications.
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