Template and Solid-State-Assisted Assembly of an M9L6 Expanded Coordination Cage for Medium-Sized Molecule Encapsulation

The M6L4 cage, self-assembling from six Pd(II) or Pt(II) 90-degree blocks and four triazine-cored triangular ligands, has an effective hydrophobic cavity of about 450 Å3 capable of encapsulating one or more small molecules. Here, from the same components, we successfully constructed an M9L6 cage with an internal volume expanded to 1540 Å3 via the self-assembly of an M8L6 precursor using pillar[5]arene as a template. This cage retains the high molecular recognition ability of the M6L4 cage while recognizing medium-sized guest molecules with molecular weights of up to ∼1600.