The accurate determination of ultra-high binding affinities in supramolecular host-guest chemistry is a challenging endeavour because direct binding titrations are generally limited to affinities <106 M-1 due to sensitivity constraints...

We report the formation of supramolecular complexation between cucurbit[n]urils (CBn) and an amphiphilic pyridinium-functionalized anthracene (AnPy) in aqueous solution. The CB7 cavity is capable of accommodating the pyridinium moiety, while CB8 can encapsulate the pyridinium and anthracene moieties at once. The encapsulation of AnPy by CB7 leads to the formation of nanoparticles, while the complexation of AnPy with CB8 leads to the formation of nanorods.

We introduce herein boron-dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding motifs for CB7. The unprotonated dyes show low fluorescence due to photoinduced electron transfer (PET), whereas the protonated dyes are highly fluorescent. Encapsulation of the binding motif inside CB7 positions the aniline nitrogen at the carbonyl rim of CB7, which affects the pK a value, and leads to a host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and pK a values is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host–dye reporter pairs can be implemented. This includes indicator displacement assays with favourable absorption and emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization with fluorophores.

A new set of hybrid guest molecules bearing organic and inorganic residues have been studied for their recognition by cyclodextrins in aqueous solution. The guest molecules consist of nitroanilines linked...

Two simple colorimetric and fluorimetric methods to probe the surface of gold nanoparticles.