Most molecules are held together by chemical bonds between atoms – ‘nano-knots’ are instead mechanically bonded by interpenetrating loops. Liverpool scientists have managed to create nanoscale knots in the laboratory by mixing together two simple starting materials – one a rigid aromatic compound and the other a more flexible amine linker.
This is an unusual example of ‘self-assembly’, a process which underpins biology and allows complex structures to assemble from more simple building blocks. Each knot is ‘tied’ three times: that is, at least three chemical bonds must be broken to untie the knot. A single knot is a complex assembly of 20 smaller molecules
Professor Andrew Cooper, Director of the University’s Centre for Materials Discovery, said: “I was amazed when we discovered these molecules; we actually set out to make something simpler. A complex structure arises out of quite basic building blocks.
“It is like shaking Scrabble tiles in a bag and pulling out a fully formed sentence. These are the surprises which make scientific research so fascinating.”