Bis(m-phenylene)-32-crown-10-based cryptands, powerful hosts for paraquat derivatives.

Four new bis(m-phenylene)-32-crown-10-based cryptands with different third bridges were prepared. Their complexes with paraquat derivatives were studied by proton NMR spectroscopy, mass spectrometry, and X-ray analysis. It was found that these cryptands bind paraquat derivatives very strongly.

First pseudorotaxane-like [3]complexes based on cryptands and paraquat: self-assembly and crystal structures.

A new cryptand, bis(1,3,5-phenylene)tri(1,4,7,10-tetraoxadecyl) (3a), has been synthesized in good yield from bis(5-hydroxy-1,3-phenylene)-26-crown-8 (2a) and tri(ethylene glycol) ditosylate using pseudo-high dilution conditions. 3a forms a strong 1:1 complex with paraquat (1) in acetone solution with a high apparent association constant, 1.4 x 10(4) M(-)(1).

Crowned dendrimers: pH-responsive pseudorotaxane formation.

With the end goal of incorporating the unique structural and physical properties of dendrimers into supramolecular assemblies, bis(m-phenylene)-32-crown-10-functionalized poly(propyleneimine) dendrimers of the first and third generations have been synthesized and their interaction with paraquat diol has been investigated. Using (1)H NMR, we determined that binding to the 4 or 16 crown ether sites occurred in an anti-cooperative fashion, most likely a result of steric influences. Upon protonation of the tertiary amines in the dendritic interior, binding became independent, i.