However, retaining the C3-symmetric conformation of 3-TPyT (θ = 120º) would result in a highly strained Td cage; therefore, the ligand assumes a desymmetrized conformation (Figure , left) as it assembles into the Pd6L4 cage. affords an analogous cage). θ denotes the angle between the C-C single bond (indicated in blue) and the N-Pd coordination bond formed in the presence of Pd 2+ . (c) Selfassembly of a tube-like D2h-symmetric cage from a cis-blocked Pd 2+ acceptor and tris(3-pyridyl)triazine (3-TPyT) (note: unless this cage binds a suitable guest, it typically assumes a bowl-like conformer ). (d) Reversible transformation between the tube-shaped cage T and the capsule-shaped cage C co-assembled from triimidazolylbenzene (TImB) and a Pd 2+ acceptor cis-blocked with N,N,N',N'-tetramethylethylenediamine (TMEDA).