title: Template control over dimerization and guest selectivity of interpenetrated coordination cages.
abstract: We have previously shown that the self-assembly of dibenzosuberone-based bis-monodentate pyridyl ligands L(1) with Pd(II) cations leads to the quantitative formation of interpenetrated coordination cages [BF4@Pd4L(1)8]. The BF4(-) anion inside the central cavity serves as a template, causing the outer two pockets to show a tremendous affinity for allosteric binding of two small chloride anions. Here we show that derivatization of the ligand backbone with a bulky aryl substituent allows us to control the dimerization and hence the guest-binding ability of the cage by the choice of the templating anion. Steric constraints imposed by L(2) prevent the large BF4(-) anion from serving as a template for the formation of interpenetrated double cages. Instead, a single isomer of the monomeric cage [Pd2L(2)4] is formed. Addition of the small anionic template Cl(-) permits dimerization, yielding the interpenetrated double cage [Cl@Pd4L(2)8], whose enlarged outer pockets show a preference for the binding of large anions such as ReO4(-).
authors.affiliation: Institute for Inorganic Chemistry, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Freye
authors.forename: Reent
authors.initials: R
authors.lastname: Michel
authors.forename: Dietmar
authors.initials: D
authors.lastname: Stalke
authors.forename: Martin
authors.initials: M
authors.lastname: Pawliczek
authors.forename: Holm
authors.initials: H
authors.lastname: Frauendorf
authors.forename: Guido H
authors.initials: GH
authors.lastname: Clever