Synthesis of Azaylide‐Based Amphiphiles by the Staudinger Reaction

Abstract

Catalyst‐ and reagent‐free reactions are powerful tools creating various functional molecules and materials. However, such chemical bonds are usually hydrolysable or require specific functional groups, which limits their use in aqueous media. Herein, we report the development of new amphiphiles through the Staudinger reaction. Simple mixing of chlorinated aryl azide with a hydrophilic moiety and various triarylphosphines (PAr3) gave rise to azaylide‐based amphiphiles NPAr3, rapidly and quantitatively. The obtained NPAr3 formed ca. 2 nm‐sized spherical aggregates (NPAr3)n in water. The hydrolysis of NPAr3 was significantly suppressed as compared with those of non‐chlorinated amphiphiles nNPAr3. Computational studies revealed that the stability is mainly governed by the decrease in LUMO around the phosphorus atom owing to the o‐substituted halogen groups. Furthermore, hydrophobic dyes such as Nile red and BODIPY were encapsulated by the spherical aggregates (NPAr3)n in water.

Aromatic micelles: toward a third-generation of micelles

“…Adamantane-based micelle (ADA) n was spontaneously and quantitatively generated in water from ADA at high concentration (970 mM). The DLS and DOSY analyses confirmed the formation of spherical micelles (ADA) n with an average core diameter of 2.5 nm, suggesting the main composition to be (ADA) 16 . Micelle (ADA) n displayed wideranging host abilities toward medium-size to huge spherical compounds (i.e., approximately 0.6 to 3 nm), such as adamantane, diamantane, fullerenes, and metal-organic polyhedra (MOP) in water, unlike previous micelles (i.e., (AA) n , (CHA) n , and (SDS) n ).…”

“…2e). 8)- 16) Importantly, despite strong self-assembling properties, aromatic micelle (AA) n can efficiently incorporate various hydrophobic dyes into the dynamic cavities in water, through multiple hostguest interactions, e.g., the hydrophobic effect and :-:/CH-: interactions (Fig. 3a).…”

Trimethylsilanol Cleaves Stable Azaylides As Revealed by Unfolding of Robust “Staudinger” Single-Chain Nanoparticles

“…Moreover, the synthesis of polyphosphazenes with high thermal stability by the fast nonhydrolysis Staudinger reaction between a bis-perfluoroaryl azide and a bis-phosphine was additionally reported by Yan and co-workers . More recently, Yamashina, Toyota and co-workers used the nonhydrolysis Staudinger reaction for the synthesis of robust azaylide-based amphiphiles that are stable against hydrolysis in water and form ca. 2 nm spherical aggregates through self-assembly.…”

“…47 Moreover, the synthesis of polyphosphazenes with high thermal stability by the fast nonhydrolysis Staudinger reaction between a bis-perfluoroaryl azide and a bis-phosphine was additionally reported by Yan and co-workers. 51 More recently, Yamashina, Toyota and coworkers 52…”