Reversible mechanical switching of magnetic interactions in a molecular shuttle.

ABSTRACT: An acid-base switchable molecular shuttle based on a [2]rotaxane, incorporating stable radical units in both the ring and dumbbell components, is reported. The [2]rotaxane comprises a dibenzo[24]crown-8 ring (DB24C8) interlocked with a dumbbell component that possesses a dialkylammonium (NH2 (+)) and a 4,4'-bipyridinium (BPY(2+)) recognition site. Deprotonation of the rotaxane NH2 (+) centers effects a quantitative displacement of the DB24C8 macroring to the BPY(2+) recognition site, a process that can be reversed by acid treatment. Interaction between stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals connected to the ring and dumbbell components could be switched between noncoupled (three-line electron paramagnetic resonance (EPR) spectrum) and coupled (five-line EPR spectrum)

SUBMITTER: Bleve V 

PROVIDER: S-EPMC4380948 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature