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.

Polymer-Bound Coumarin–Triphenyliminophosphorane Derivatives as Turn-On Fluorescence Sensors for Water Content Detection via Non-Hydrolytic Staudinger Reaction

“…In recent years, the non-hydrolytic Staudinger reaction (NSR) has attracted much attention as one of the efficient click-type reactions in bioorthogonal chemistry. − The strategy to stabilize the iminophosphorane (IPP) intermediate accompanied with a resonance contribution of aza-ylide of Staudinger reaction is mainly based on the inductive effect of the electronegative substituents adjacent to the IPP bond, which prevents the nucleophilic attack of H 2 O, yielding undesired hydrolyzed products. In addition, as the Staudinger reaction involves an initial azide group, another click reaction involving alkyne/azide cycloaddition can be combined with the NSR for creating versatile functional molecules. , Toyota and co-workers used the NSR strategy to prepare amphiphilic aza-ylide derivatives and confirmed the long-term stability of the aza-ylide structure in aqueous solution . The amphiphiles could form spherical aggregates with a size of approximately 2 nm through a self-assembly process.…”

“…8,9 Toyota and coworkers used the NSR strategy to prepare amphiphilic azaylide derivatives and confirmed the long-term stability of the aza-ylide structure in aqueous solution. 10 The amphiphiles could form spherical aggregates with a size of approximately 2 nm through a self-assembly process. Our group has used the NSR concept to synthesize a series of coumarin−triphenyliminophosphorane (TPIPP) derivatives.…”

Kinetic and mechanistic studies of the Staudinger reduction: On the chemistry of aryl phosphazides

“…The Staudinger reduction is a well-established method for the synthetic reduction of azides to amines [1,2] and has been widely used in biological and host-guest applications, [3][4][5] in part due to the mild conditions employed by such reactions, as well as their tolerance for aqueous environments. The field of phosphine-based (aza-Wittig) chemistries and their biological applications has been the subject of a recent review.…”

Coordination Cage‐Based Emulsifiers: Templated Formation of Metal Oxide Microcapsules Monitored by In Situ LC‐TEM

“…[19,20] Surfactants or amphiphiles consist of two different moieties, one with hydrophilic/polar and the second with hydrophobic/ non-polar character, connected via covalent and dynamic covalent bonding, as well as noncovalent interactions. [21][22][23][24][25] The latter strategy opens the possibility to combine polar and nonpolar components in a modular self-assembly approach. Recently, our group has reported a multicomponent coordination cage (CGA-1; section 1.2, Supporting Information) of anisotropic shape, comprising a polar head unit (four methoxy groups close to two cationic Pd(II) centers) and non-polar dodecyl appendices, capable of stabilizing non-aqueous emulsions.…”

“…Surfactants or amphiphiles consist of two different moieties, one with hydrophilic/polar and the second with hydrophobic/non‐polar character, connected via covalent and dynamic covalent bonding, as well as noncovalent interactions [21–25] . The latter strategy opens the possibility to combine polar and non‐polar components in a modular self‐assembly approach.…”