Synthesis and characterization of a paramagnetic receptor based on cyclobis(paraquat-p-phenylene) tetracation

Covalent Inhibition of the Lymphoid Tyrosine Phosphatase

“…In Scheme we reported the synthetic procedure for the introduction of one or two side arms components containing a TEMPO moiety 34. Proof of the complexation ability of these spin‐labelled CBPQT 4+ ‐based macrocycles toward electron‐rich molecules, such as dimethoxynaphthalene (DMN), was obtained directly by NMR measurements.…”

“…This was the case for a mono‐ and bis‐spin‐labelled, π‐electron‐deficient, tetracationic cyclophane ring, cyclobis(paraquat‐ p ‐phenylene) (CBPQT 4+ ), one of the most versatile hosts involved in the preparation of molecular devices proposed by the Stoddart group 33. To realize it, the bis‐pyridinium precursors salts, either in the unsubstituted ( pre‐CBPQT‐1 ) or in the one‐armed ( pre‐CBPQT‐2 ) form, were linked with a benzyl dibromide containing the TEMPO functionality (Scheme ) 34…”

“…As an example, Figure 2 shows the spectra of monofunctionalized CBPQT‐1 and of the corresponding hydroxylamine derivative after reduction by phenylhydrazine 34. In the spectrum of the diamagnetic analogue the proton signals corresponding to the piperidine‐ N ‐hydroxyl ring are detected and the spectral resolution results largely improved.…”

Improving Spin Probe Methodologies to Investigate Supramolecular Assemblies

“…Finally, a spin‐labelled, p ‐electron‐deficient, tetracationic cyclophane ring, cyclobis(paraquat‐ p ‐phenylene) (CBPQT 4+ ), one of the most versatile hosts involved in the synthesis of molecular devices, was prepared by our group (Scheme ) . Complexation of electron rich guest molecules like dimethoxynaphthalene was demonstrated by measuring line narrowing of nuclear magnetic resonances of CBPQT 4+ due to the displacement of the nitroxide probe from the host cavity after the binding event.…”