Trapping White Phosphorus within a Purely Organic Molecular Container Produced by Imine Condensation

Abstract

Three tetrahedral organic cages have been obtained by condensing a triamino linker with a set of three ostensibly analogous triformyl precursors. Despite the large number of imine bonds formed, the corresponding cages were obtained in exceptionally high yields. Both theory and experimental results demonstrate that intramolecular CH⋅⋅⋅π interactions within all of the cage frameworks play an important role in abetting the condensations and contributing to the near-quantitative synthetic yields. The three cages of this study exhibit high thermodynamic and kinetic stability. A variety of small neutral guest molecules with complementary sizes and geometries may be used as templates in the cage forming reactions. Among the guests that may be used in this way is white phosphorus (P₄ ), whose inherent reactivity towards oxygen is almost fully attenuated when bound within one of the cages.

Keywords: host-guest systems; molecular recognition; organic cages; self-assembly; white phosphorus.