title: Solvent-dependent self-assembly behaviour and speciation control of Pd6L8 metallo-supramolecular cages.
abstract: The C3-symmetric chiral propylated host-type ligands (±)-tris(isonicotinoyl)-tris(propyl)-cyclotricatechylene (L1) and (±)-tris(4-pyridyl-4-benzoxy)-tris(propyl)-cyclotricatechylene (L2) self-assemble with Pd(II) into [Pd6L8](12+) metallo-cages that resemble a stella octangula. The self-assembly of the [Pd6(L1)8](12+) cage is solvent-dependent; broad NMR resonances and a disordered crystal structure indicate no chiral self-sorting of the ligand enantiomers in DMSO solution, but sharp NMR resonances occur in MeCN or MeNO2. The [Pd6(L1)8](12+) cage is observed to be less favourable in the presence of additional ligand, than is its counterpart, where L=(±)-tris(isonicotinoyl)cyclotriguaiacylene (L1 a). The stoichiometry of reactant mixtures and chemical triggers can be used to control formation of mixtures of homoleptic or heteroleptic [Pd6L8](12+) metallo-cages where L=L1 and L1 a.
authors.affiliation: School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT (UK).
authors.forename: James J
authors.initials: JJ
authors.lastname: Henkelis
authors.forename: Julie
authors.initials: J
authors.lastname: Fisher
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Warriner
authors.forename: Michaele J
authors.initials: MJ
authors.lastname: Hardie
keywords: coordination cage; ligand exchange; self-assembly; self-sorting; supramolecular chemistry