The invention provides complexes in which ligands (e.g., calixarene-related compounds) are coordinated to a metal colloid, e.g. a gold colloid. In exemplary embodiments, two or more ligands complexed to the metal colloid are larger than the metal colloid, thus providing an accessible metal center. The complexes can be immobilized on a substrate. The complexes of the invention are useful as tunable and highly robust isolated metal colloids that find use in binding of molecules and catalysis of chemical reactions.