An assembly of two or more chemically independent molecules in which a long chain molecule is encircled by one or more rings. The chain component is terminated on both ends with bulky functional groups to prevent unthreading of the ring(s).

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An assembly of molecules around an 'axle'. Applications include colourfastness of fabric dyes by threading a rod-like azo dye molecule through a ring of six glucose molecules (a cyclodextrin). This assembly is a rotaxane. The cyclodextrin sleeve protects the dye, yet, despite its bulkiness, allows the colourant to fasten on to the cellulose in cotton fibres much better. HP have used memory bits made of rotaxanes, rather than silicon - the first significant demonstration of 'molecular electronics'. In this application the rotaxane structures are trapped at the intersection of platinum and titanium wires that are only 40nm wide.

Source

An assembly of molecules around an 'axle'. Applications include colourfastness of fabric dyes by threading a rod-like azo dye molecule through a ring of six glucose molecules (a cyclodextrin). This assembly is a rotaxane. The cyclodextrin sleeve protects the dye, yet, despite its bulkiness, allows the colourant to fasten on to the cellulose in cotton fibres much better. HP have used memory bits made of rotaxanes, rather than silicon - the first significant demonstration of 'molecular electronics'. In this application the rotaxane structures are trapped at the intersection of platinum and titanium wires that are only 40nm wide.

Source