Extremely robust and post-functionalizable gold nanoparticles coated with calix[4]arenes via metal–carbon bonds

Gold nanoparticles stabilized with a thin layer of post-functionalizable calix[4]arenes were prepared through the reductive grafting of a calix[4]arene-tetra-diazonium salt. These particles show exceptional stability towards extreme pH, F−, NaCl, and upon drying. Post-functionalization of the calix-layer was demonstrated, opening the way to a wide range of applications