分子结（molecular knot，也称为knotane）为一种类似绳结的机械互锁分子结构。三叶结组态的分子结为手性分子，至少有二个对映异构，像DNA和一些特定蛋白都是自然生成的分子结。乳铁蛋白和其线性的异构物有不同的性质。其他的合成分子结因为其球状外形及奈米尺寸，因此是奈米科技中潜在的建设方块。第一个合成分子结是由Sauvage在****年合成。

knotane一词是由Fritz Vögtle等在2000年在应用化学期刊中创建，类似Rotaxane（轮烷）、catenane（索烃），不过IUPAC尚未核定此一词语。

In chemistry, a molecular knot, or knotane, is a mechanically-interlocked molecular architecture that is analogous to a macroscopic knot. A molecular knot in a trefoil knot configuration is chiral, having at least two enantiomers. Examples of naturally formed knotanes are DNA and certain proteins. Lactoferrin has an unusual biochemical reactivity compared to its linear analogue. Other synthetic molecular knots have a distinct globular shape and nanometer sized dimensions that make them potential building blocks in nanotechnology. The first knot was synthesised by Sauvage in ****.