Self-assembly of the smallest and tightest molecular trefoil knot

Molecular knots, whose synthesis presents many challenges, can play important roles in protein structure and function as well as in useful molecular materials, whose properties depend on the size of the knotted structure. Here we report the synthesis by self-assembly of molecular trefoil metallaknot with formula [Au₆{1,2-C₆H₄(OCH₂CC)₂}₃{Ph₂P(CH₂)₄PPh₂}₃], Au₆, from three units of each of the components 1,2-C₆H₄(OCH₂CCAu)₂ and Ph₂P(CH₂)₄PPh₂. Structure determination by X-ray diffraction revealed that the chiral trefoil knot contains only 54 atoms in the backbone, so that Au₆ is the smallest and tightest molecular trefoil knot known to date.