Using “Threading Followed by Shrinking” to Synthesize Highly Stable Dialkylammonium‐Ion‐Based Rotaxanes

Abstract

Scheme 3. Shrinking of macrocycle 2 into macrocycles 8 and 9.Scheme 4. Slippage synthesis of the [2]rotaxane [11-H]

Challenges and Opportunities in the Post‐Synthetic Modification of Interlocked Molecules

“…Thesame authors later extended their work to the open-chain photochemical extrusion of two SO 2 moieties,t hereby achieving two shrinkages in the same surrounding macrocycle. [52]…”

“… [51] The photochemical extrusion of SO 2 from the arylmethyl sulfone 117 provided a diradical intermediate that recombined to form the desired C−C bond. The same authors later extended their work to the open‐chain photochemical extrusion of two SO 2 moieties, thereby achieving two shrinkages in the same surrounding macrocycle [52] …”

A Redox-Controllable Molecular Switch Based on Weak Recognition of BPX26C6 at a Diphenylurea Station

“…Because of the many potential applications of rotaxane-based molecular switches (e.g., in material transportation [ 1 , 2 ], molecular memory [ 3 ], sensing [ 4 , 5 ], and gelation [ 6 , 7 ]), there is keen interest in finding new recognition units for the assembly of these functional interlocked molecules and in developing new methods for their reversible operation [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Although the basic switching cycle in a simple bistable [2]rotaxane-type molecular switch requires only an appropriately large and invertible difference in stabilization energy for the complexation of the macrocyclic component at the two stations in the dumbbell-shaped component, in practice one of these stations must have sufficiently strong binding affinity to the macrocycle to ensure efficient synthesis of the [2]rotaxane in the first place.…”