The mean time spent by a macromolecule at a solid/liquid interface is analyzed in the region of adsorption saturation. The method consists of carrying out preliminary adsorption with radioactively labeled high‐molecular‐weight polyacrylamide and subsequently exposing the surface to a solution of unlabeled polyacrylamide. It was found that, apart from a small fraction of polymers “loosely” attached, the exchange between labeled and unlabeled polymers takes place at the interface at a very slow rate. Furthermore, desorption of surface molecules occurs only in the presence of a solution, and then the rate of desorption increases proportionally to the number of molecules in the solution. A mechanism based on a bimolecular chemical exchange process is proposed.

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The macrobicyclic molecules (la-c) have been synthesized; they are heteroditopic ligands combining a 'soft' and a 'hard' binding subunit, which form lateral dinuclear cryptates such as [Rh+-CO, Mn+ C (la-c)] by selective complexation to a given site.

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