An Unlockable–Relockable Iron Cage by Subcomponent Self‐Assembly

Abstract

Lineare Diamin‐ und Formylpyridin‐Einheiten bilden mit Eisen(II) einen tetraedrischen Käfig (siehe Schema), der hydrophobe Gastspezies hoch spezifisch in seinem Hohlraum aufnimmt und von der wässrigen Umgebung abschirmt. Beim Öffnen des Käfigs durch Zusatz eines Triamins wird die eingeschlossene Spezies freigesetzt. Alternativ zerfällt der Käfig bei Zugabe von Säure, doch dieser Prozess kann durch Base rückgängig gemacht werden, sodass die Gastspezies reversibel freigesetzt und eingeschlossen wird.

Guanidinium Binding Modulates Guest Exchange within an [M4L6] Capsule

“…The exterior of our previously reported tetrahedral [Fe II 4 L 6 ] 4À capsule 1 [4] is decorated with 12 sulfonate groups that are ideally oriented to undergo hydrogen bonding with the C 3 -symmetric guanidinium cation (Gnd + ). Interactions of this type have been frequently observed in both biological and synthetic systems.…”

“…[5] Synthetic guanidinium-based receptors have been extensively used to bind anions in aqueous media, [6] and in some cases they display enantioselectivity [7] and catalytic activity. [4] Host 1 is water soluble and is capable of encapsulating a variety of guests such as cyclopentane, cyclohexane, benzene, P 4 , SF 6 , and furan within its hydrophobic cavity. [2b-d] The synthesis of host 1 (Scheme 1) as the tetramethylammonium salt has been previously reported.…”

Self-assembled metal–organic polyhedra: An overview of various applications

“…The stability of tetrahedral cage derives from the strong binding between the imine ligands and metal ions. The addition of acid or chelating agent such as tris(2-ethylamino)amine unlocks the cage into its precursor units but, becomes reassembled in basic medium [119]. Encapsulation of furan by cage 4 prevents it to form Diels-alder adduct with maleimide.…”

Ligand Constraints and Synthesis of Metal–Organic Polyhedra

“…The various aspects including feasibility and usefulness of this particular approach in the synthesis of helicates, catenanes, and macrocycles have been well exploited and elucidated. [120a,122] The Nitschke group used this approach to synthesise a range of discrete molecular architectures starting from one of the very vital tetrahedral cage synthesised by reaction between 2-formylpyridine and 4,4 0 -diaminobiphenyl-2,2 0 -disulfonic acid with Fe II in the presence of base [123] (Fig. 21).…”