Extraction and dispersion of large gold nanoparticles in nonpolar solvents

Gold nanoparticles tip to 70 nm in diameter could be extracted fi-om aqueou s solutions into nonpolar organic solvents by tetrathiolated resorcinarenes 1 and 2. The resorcinarene-coated nanoparticles formed stable dispersions in toluene and chloroform and could be passed through a crosslinked polysty rene column without significant degradation, but exhibited variable resista nce to alkanethiol-induced flocculation. Gold nanoparticles encapsulated by resorcinarene 2 were found to be exceptionally stable even in the presence of propanethiol and dodecanethiol, with an approximate dispersion half-lif e of one month at room temperature.