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 (P ), whose inherent reactivity towards oxygen is almost fully attenuated when bound within one of the cages.

Shape‐Persistent [4+4] Imine Cages with a Truncated Tetrahedral Geometry

“…In consequence, it is not surprising that in the combination 1‐H and 2‐Et, again an insoluble imine polymer is formed rather than cage 3‐Et‐H . In contrast, the combination 1‐Et and 2‐Et again gives the corresponding cage 3‐Et‐Et in 46 % isolated yield, thus suggesting that the functional groups need to be highly pre‐oriented at least in one of the reactants …”

A mutually stabilized host-guest pair

“…These hosts often have preorganized pockets or cavities, where various guests with complementary geometries and sizes could be accommodated and isolated from the bulk environment. As a consequence, a variety of labile molecules such as cyclobutadiene (8), hemiaminal (9,10), white phosphorus (11)(12)(13), benzyne (14), sulfur clusters (15), and iminiums (16) were able to be stabilized. Despite these many examples of the protected guest within a host, the reports of using a guest to stabilize a host are rare, except for a few self-assembled cages (17,18) containing imine linkages, which become more stable against hydrolysis in aqueous solution when the cage cavities are occupied by hydrophobic guests.…”

Dynamic Covalent Self‐Assembly Based on Oxime Condensation

“…[2][3][4][5][6][7][8] Its reversible nature allows the systems to perform error-checking and self-correcting during searching for their thermodynamic minimum. As ac onsequence, avariety of complex molecules [9][10][11][12][13] are obtained in high yields, especially when these self-assembled molecules are sophisticatedly designed to represent the most thermodynamically favoured products.One of the major disadvantages of iminebased DCC is that, this dynamic bond is apt to undergo hydrolysis in aqueous solution. Therefore,the self-assembled products containing imine can hardly realize their functions in water, the medium of life.H ydrazone (-C=NÀN-), [14] am ore robust counterpart of imine,w as thus employed to develop water-compatible DCC approaches.T he higher stability of hydrazone results from the delocalization of the lone electron pair in the adjacent nitrogen atom onto to the C = Nd ouble bond, resulting in acharge-separated resonance form, namely -C À ÀN=N + -.…”