Thinking outside the Blue Box: from molecular to supramolecular pH-responsiveness

authors	Blanco-Gomez, A; Neira, I; Barriada, JL; Melle-Franco, M; Peinador, C; Garcia, MD
nationality	International
journal	CHEMICAL SCIENCE
keywords	ASSEMBLED PD-II; SWITCHES; COMPLEXATION; ROTAXANES; CATENANE; DRIVEN
abstract	We present herein the development of a new polycationic cyclophane: the red box, second in a series of hydrazone-based analogues of the well-known organic receptor cyclobis(paraquat-p-phenylene) cyclophane (blue box). The macrocycle has been prepared in an excellent yield in aqueous media, and shows both a remarkable pH-responsiveness and unusual hydrolytic stability of the two hydrazone C=N bonds, associated with charge delocalization of the amine lone pair. Whilst in aqueous media the red box is able to complex a variety of aromatic substrates, both in its acidic and basic form, in organic media the cyclophane is only able to capture those in the acidic form, resulting in supramolecular pHresponsiveness.
publisher	ROYAL SOC CHEMISTRY
issn	2041-6520
isbn	2041-6539
year published	2019
volume	10
issue	46
beginning page	10680
ending page	10686
digital object identifier (doi)	10.1039/c9sc04489b
web of science category	Chemistry, Multidisciplinary
subject category	Chemistry
unique article identifier	WOS:000499471800018