Rotaxane Formation under Thermodynamic Control

Thermodynamic control operates in the synthesis of a [2]rotaxane based upon the dibenzylammonium ion/crown ether recognition motif.
When dibenzo[24]crown-8 is added to an acetonitrile solution containing a diimine dumbbell-like component, the dynamic nature of the system
(i.e., imine hydrolysis/reformation) offers the ring component access to the NH2+ center, allowing the self-assembly of the corresponding
“dynamic” [2]rotaxane to occur. The “fixing” of this [2]rotaxane can be achieved upon reduction of the imine bonds, affording a kinetically
inert [2]rotaxane.