Terpyridine-based metallo-organic cages and supramolecular gelation by coordination-driven self-assembly and host–guest interaction†
Host–guest complexation based on terpyridine (tpy) three-dimensional (3D) metallo-cages has received less attention due to the complicated structure and solubility issues. Herein, a three-armed metallo-organic ligand (L) was synthesized via three 120°-bent bis-tpy groups as a rigid tetrakis-tpy core, which possesses one benzo-21-crown-7 (B21C7) for further host–guest interaction. The metallo-organic cages [M3L2] with molecular weights up to 13 000 Da and giant cavities were prepared in near-quantitative yield by self-assembly of L with metal ions, such as Zn2+ and Fe2+. The 3D metallo-supramolecules were characterized and their formation was supported by NMR, DOSY, ESI-MS and TEM. Hosts [M3L2] were threaded through a difunctional alkylammonium salt by host–guest interactions to polymerize, and subsequently generate novel metallo-gels between [Zn3L2] and bis-ammonium salt (N2).
- This article is part of the themed collection: Molecular metal-containing soft materials