ProBox: A Rigid yet Dynamic Cyclophane Capable of Adaptive and Redox-Switchable Host–Guest Binding

Abstract

A pyrrolodithiin-derived box-like cyclophane (ProBox), featuring an adaptive geometry with stimuli-responsiveness, was designed and successfully constructed. The dynamic and foldable dithiin subunit endowed the cyclophane with a compressible cavity which can transform from a hex-nut geometry to a nearly rectangular box upon complexing guests with various sizes and shapes. The resulting pseudorotaxane complexes could be dethreaded via electrochemical oxidation. Such an adaptive cavity along with redox-switchable host–guest binding of ProBox could enable further applications in complex molecular switches and machines.

Synthesis and Properties of Novel Alkyl-Substituted Hexaazacyclophanes and Their Diradical Dications

“…Researchers have successfully prepared cyclic compounds with various structural types such as ladder-like, ring-like, cage-like, and dendritic ( Figure 1 ) [ 17 , 18 , 19 , 20 , 21 ]. When these cyclic compounds form cyclic radicals through electronic oxidation, the open-shell compounds exhibit unique magnetic, optical, and electronic properties that can be used to construct paramagnetic reagents and magnetic materials [ 22 , 23 , 24 , 25 , 26 , 27 ]. Due to the introduction of nitrogen atoms, nitrogen-containing heterocyclic compounds have relatively low oxidation potentials, and the substitution of methylene by nitrogen atoms strengthens the redox activity [ 28 ].…”