INORGANIC INCLUSION CHEMISTRY - A NOVEL ANION INCLUSION SYSTEM

A bowl-shaped calixresorcinarene, 1, has been derivatized to incorpora te four phosphonite units to give a phosphonitocavitand, 2, which can act as a tetradentate ligand. Thus, 2 has been used in the synthesis o f several tetracopper(I) and tetrasilver(I) complexes, such as [PyH]()[2 . Cu-4(mu-Cl)(4)(mu(3)-Cl)](-) (4) and [PyH](+)[2 . Ag-4(mu-Cl)(4) (mu(4)-Cl)](-) (5). The tetracopper(I) complex, 4, and tetrasilver(I) complex, 5, have been shown to act as size-selective hosts for halide inclusion. Iodide is preferred over chloride as guest in 4 since it is large enough to coordinate to all four copper atoms in an unusual mu( 4)-face-bridging bonding mode. The anion inclusions found for the tran sition metal rimmed bowl complexes are unique in supramolecular chemis try. The anion occluded complex 5a can act as a nucleophile to convert RI to RCl; the reaction occurs in high yield, follows the reactivity sequence t-BuI > i-PrI > MeI, and occurs with predominant retention of stereochemistry in the reaction of (S)-(+)-2-iodooctane. The overall reaction leads to the favorable replacement of the occluded mu(3)-Cl l igand in 5a by mu(4)-L.