I hope the former record-holders aren’t too cross: a team of researchers recently made the smallest, tightest knot yet known, landing themselves top spot in the Guinness Book of World Records.
The knot is composed of 54 atoms, chained together and ensnared in a trefoil, the simplest nontrivial knot. The knot has no loose end; it is a continuous loop, passing through itself in mesmerizing arcs. The team’s work describing the self-assembled “metallaknot” was published in Nature Communications.
It is made up of gold, carbon, and phosphorus, as reported by New Scientist. The knot is formulaically described as [Au6{1,2-C6H4(OCH2CC)2}3{Ph2P(CH2)4PPh2}3], or Au6 for short, in reference to the six gold atoms in the knot.
You may wonder how a team determines the tightness of a knot at the molecular scale. As the researchers state in their paper, the knots are “classified according to the minimum number of crossings when the reduced form of the structure is projected onto a two-dimensional surface.”
In 2017, a team of researchers crafted a knot with 24 atoms per crossing, which made it into the Guinness Book. In 2020, a different team managed to produce a 69-atom-long knot with a backbone crossing ratio (or BCR) of 23, making it the record holder. The smaller the BCR, the tighter the knot.
The newest—and indeed, smallest and tightest knot—beats the 2020 record. The new knot is just 54 atoms long, and has a remarkably low BCR of just 18. It is tighter than the BCR of the tightest organic trefoil knots by a BCR margin of 7.3.
According to ScienceAlert, the knot is edging close to the theoretical limit of knot length. Previous research suggested that the smallest trefoil knot ought to contain “at least 50” atoms.
The recent accomplishment is knot—er, not—the only knot to hold a place in the Guinness Book. The largest human knot was made in 2019 and involved 123 people. The largest Chinese knot was made by a kindergarten class and was over 130 feet tall and 136 feet across, according to the book. The pantheon of notable knots is obviously a large one, but surely the new record cannot be beaten…or can it?