Desymmetrization of an Octahedral Coordination Complex Inside a Self‐Assembled Exoskeleton |
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| Authors: | Dr. Mark D. Johnstone Eike K. Schwarze Jennifer Ahrens Prof. Dr. Dirk Schwarzer Dr. Julian J. Holstein Dr. Birger Dittrich Dr. Frederick M. Pfeffer Prof. Dr. Guido H. Clever |
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| Affiliation: | 1. http://www.deakin.edu.au/profiles/fred‐pfefferhttp://www.clever‐lab.de;2. Research Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Victoria, Australia;3. Institute for Inorganic Chemistry, Georg-August University G?ttingen, G?ttingen, Germany;4. Faculty of Chemistry and Chemical Biology, TU Dortmund, Dortmund, Germany;5. Max-Planck-Institute of Biophysical Chemistry, G?ttingen, Germany;6. Institute for Inorganic and Structural Chemistry, Heinrich-Heine-Universit?t Düsseldorf, Düsseldorf, Germany |
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| Abstract: | The synthesis of a centrally functionalized, ribbon‐shaped [6]polynorbornane ligand L that self‐assembles with PdII cations into a {Pd2 L 4} coordination cage is reported. The shape‐persistent {Pd2 L 4} cage contains two axial cationic centers and an array of four equatorial H‐bond donors pointing directly towards the center of the cavity. This precisely defined supramolecular environment is complementary to the geometry of classic octahedral complexes [M(XY)6] with six diatomic ligands. Very strong binding of [Pt(CN)6]2? to the cage was observed, with the structure of the host–guest complex {[Pt(CN)6]@Pd2L4} supported by NMR spectroscopy, MS, and X‐ray data. The self‐assembled shell imprints its geometry on the encapsulated guest, and desymmetrization of the octahedral platinum species by the influence of the D4h‐symmetric second coordination sphere was evidenced by IR spectroscopy. [Fe(CN)6]3? and square‐planar [Pt(CN)4]2? were strongly bound. Smaller octahedral anions such as [SiF6]2?, neutral carbonyl complexes ([M(CO)6]; M=Cr, Mo, W) and the linear [Ag(CN)2]? anion were only weakly bound, showing that both size and charge match are key factors for high‐affinity binding. |
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| Keywords: | anion recognition coordination cages endohedral functionalization host– guest chemistry supramolecular chemistry |
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