Synthesis of Oxygen-Free [2]Rotaxanes: Recognition of Diarylguanidinium Ions by Tetraazacyclophanes

Abstract

Simple cyclophanes containing four distant amino N atoms or ether O atoms behave as hosts for the threading of guest diarylguanidinium ions. The recognition system exhibits high synthetic flexibility, allowing unique O-free [2]rotaxanes to be synthesized efficiently (yields of up to 80%) through both "threading-followed-by-stoppering" and "clipping" approaches.

Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State

“…Hence, we found the conditions to induce an M helix in a poly- 1 film by using a NaBArF salt as an external stimulus. This metal salt can deliver a sodium cation in the naked form, which allowed for its coordination to poly- 1 even in the solid state. − Therefore, the use of the noncoordinating BArF – as the counteranion is a key for the induction of a preferred-handed helicity in poly- 1 in the solid state upon interaction with metal cations.…”

“…This metal salt can deliver the sodium cation as a naked form, allowing its coordination to poly-1 even in the solid state. [33][34][35] Therefore, the use of the noncoordinating BArFas the counter anion is a key for the induction of a preferred-handed helicity in poly-1 in the solid state upon interaction with metal cations.…”

Rotaxane formation by an allosteric pseudomacrocyclic anion receptor utilising kinetically labile copper(i) coordination properties

“…In the usual clipping methods, an irreversible covalent bond forming ring-closing step of an acyclic precursor for the ring is required to afford the rotaxanes in high yields in some cases. 9,12–21 The capping method also requires the second step to fix the rotaxane structure. A spontaneous rotaxane forming method from a kinetically labile ring and an axle is potentially an alternative convenient method for rotaxane preparation.…”

Highly Efficient Förster Resonance Energy Transfer Modulations of Dual-AIEgens between a Tetraphenylethylene Donor and a Merocyanine Acceptor in Photo-Switchable [2]Rotaxanes and Reversible Photo-Patterning Applications

“…Therefore, rotaxanes, catenanes, necklaces, and molecular knots belong to the large range of MIMs that have played critical roles to construct responsive materials for the application of molecular sensors, actuators, machines, and smart materials. , The rotaxane is one of the major prototype of MIMs, comprising one (or more) macrocyclic host(s) trapped into the threaded molecule(s) by terminal stoppers, which have attracted more attention because of their unique molecular structures . A variety of rotaxanes have been developed with highly structural complexity by self-sorting, template synthesis, or dynamic combinatorial chemistry and showed extensive applications in various fields, such as chemosensors, mechanical materials, drug delivery, nanotechnology, and biotechnology. − …”