Chemistry - A European Journal
Punidha Sokkalingam, Seong-Jin Hong, Abdullah Aydogan, Jonathan L. Sessler, Chang-Hee Lee
Gold nanoparticles decorated with a double-armed, deep-cavity calixpyrrole were prepared and fully characterized. Transmission electron microscopy imaging revealed that the average diameter of the particles was approximately 4nm both before and after attachment of the receptor to the surface. The calixpyrrole-functionalized nanoparticles exhibited highly elevated sensing behavior (approximately 1000 times in dichloromethane) relative to its monomeric congener while maintaining its guest selectivity. The receptornanoparticle conjugate (nanoreceptor) showed significant aggregation upon addition of the biphenolate anion, an effect ascribed to anion-mediated interparticle linking. The receptornanoparticle conjugate is also capable of extracting the fluoride anion (as its tetrabutylammonium salt) from an aqueous layer to an organic medium. Control experiments revealed that this extraction is not possible when using the analogous monomeric receptor.