Assembly of dynamic helical β-peptides with switchable handedness into multiple types of metal-peptide frameworks

Metal-directed assemblies of helical peptides are emerging chiral biomimetic materials, yet dynamic helical peptides remain underexplored. Here we report the coordination-driven assembly of dynamic 12/10-helical β-pentapeptides into distinct metal–peptide frameworks (MPFs) with silver ions. Ligand 1, consisting of cis-2-aminocycloheptanecarboxylic acid with alternating chirality, exhibits solvent-dependent screw-sense preference: (P)-helix in protic and (M)-helix in aprotic solvents. The two helical conformers are not enantiomers and assemble into two distinct MPFs (Ag-1M and Ag-1P), while a racemic ligand mixture (1 and ent-1) yields a third MPF (Ag-rac-1PM). A series of modified ligands (2-5), incorporating various central residues, form MPFs analogous to Ag-1M or Ag-1P, with pore environments modulated by side chains. Particularly, an MPF incorporating polar N-acetyl azepane moieties (Ag-5M) selectively recognizes a chiral guest through post-crystallization. These results highlight dynamic helical β-peptides as versatile building blocks for diverse chiral MPFs, with tunable pore environments through rational peptide design. Metal-directed assemblies of helical peptides have emerged as chiral biomimetic materials, but examples of dynamic helical peptides are rare, despite their ability to adopt multiple conformations. Here the authors report the coordination-driven assembly of a dynamic helical β-pentapeptide into metal peptide frameworks with silver ions.