Formation of Giant and Small Cyclic Complexes from a Flexible Tripeptide Ligand Controlled by Metal Coordination and Hydrogen Bonds

), in which "shrunk" cavities with a 10-fold difference in diameter (<0.2 nm) were formed by tuning the tripeptide conformation through additional metal coordination to the tripeptide framework. Dynamic light scattering and mass spectrometry studies indicated that the giant cyclic complexes were also present in the solution state.