Abstract
A fluxional bis-monodentate ligand, based on the archetypal shape-shifting molecule bullvalene, self-assembles with M2+ (M=Pd2+ or Pt2+) to produce a highly complex ensemble of permanently fluxional coordination cages. Metal-mediated self-assembly selects for an M2L4 architecture while maintaining shape-shifting ligand complexity. A second level of simplification is achieved with guest-exchange; the binding of halides within the M2L4 cage mixture results in a convergence to a cage species with all four ligands present as the “B isomer”. Within this confine, the reaction graph of the bullvalene is greatly restricted, but gives rise to a mixture of 38 possible diastereoisomers in rapid exchange. X-ray crystallography reveals a preference for an achiral form consisting of both ligand enantiomers. Through a combination of NMR spectroscopy and DFT calculations, we elucidate the restricted isomerisation pathway of the permanently fluxional M2L4 assembly.
Original language | English |
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Article number | e202115468 |
Number of pages | 5 |
Journal | Angewandte Chemie - International Edition |
Volume | 61 |
Issue number | 9 |
DOIs | |
Publication status | Published - 21 Feb 2022 |
Externally published | Yes |
Keywords
- Convergence
- Coordination cage
- Fluxional molecule
- Host-guest chemistry
- Self-assembly