Self‐Assembly and Disassembly of Vesicles as Controlled by Anion–π Interactions

Abstract

Anion-π interactions have been widely studied as new noncovalent driving forces in supramolecular chemistry. However, self-assembly induced by anion-π interactions is still largely unexplored. Herein we report the formation of supramolecular amphiphiles through anion-π interactions, and the subsequent formation of self-assembled vesicles in water. With the π receptor 1 as the host and anionic amphiphiles, such as sodium dodecylsulfate (SDS), sodium laurate (SLA), and sodium methyl dodecylphosphonate (SDP), as guests, the sequential formation of host-guest supramolecular amphiphiles and self-assembled vesicles was demonstrated by SEM, TEM, DLS, and XRD techniques. The intrinsic anion-π interactions between 1 and the anionic amphiphiles were confirmed by crystal diffraction, HRMS analysis, and DFT calculations. Furthermore, the controlled disassembly of the vesicles was promoted by competing anions, such as NO3 (-) , Cl(-) , and Br(-) , or by changing the pH value of the medium.

Anion–π catalysis: bicyclic products with four contiguous stereogenic centers from otherwise elusive diastereospecific domino reactions on π-acidic surfaces

“…Contributions of anion–π interactions 1,2 to catalysis were first demonstrated explicitly in 2013. 3 Since then, anion–π catalysis has been explored with enolate, 4,5 enamine, 6 iminium, 7 transamination 8 and oxocarbenium 9 chemistry, and the first anion–π enzyme has been created.…”

Anion Receptor Chemistry

“…perchlorate template the formation of molecular squares [Fe 4 (148) 4 (CH 3 CN) 8 ]I [anion] 8 (Figure 50A), whereas hexafluoroantimonate, hexafluorophosphate, and hexafluoroarsenate template the formation of molecular pentagons [Fe 5 (148) Structures of Solomon Link [2]catenane 143, Pentafoil Knot 144, and Star of David [2] catenane 145 Shown as Their PF 6 À Salts (CH 3 CN) 10 ]I[anion] 10 (Figure 50B) 19. F magic-angle spinning NMR studies showed that encapsulated templating anions had downfield chemical shifts of 3.5-4.0 ppm in comparison with non-encapsulated anions.Anion-p interactions have also been used by He et al75 to control the assembly of vesicular structures. The interaction between macrocycle 149 and amphiphiles such as SDS was studied, and the authors found that 149 formed a complex with SDS via anion-p interactions (Figure 51).…”

Anion–π Catalysis of Enolate Chemistry: Rigidified Leonard Turns as a General Motif to Run Reactions on Aromatic Surfaces

“…Thus begins Jean de La Fontaine (1621-1695 AD) to recount the ancient Greek fable from Aesop (620-560 BC). [5,6] The functional relevance of anion-p interactions has been demonstrated for self-assembly, [7] transport, [8,9] and, most recently, also for catalysis. In the context of chemical transformations,Aesops fable perfectly describes the challenge to selectively catalyze adisfavored reaction.…”

“…[2] Instead, decarboxylation is the favored reaction, leading to the less useful thioester 4a as the major product. The significance of the results described herein suggests that the newly introduced, rigidified Leonard turns [13] represent agen-eral design principle for enabling reactions to occur on aromatic surfaces and thus for harnessing the full potential of anion-p, [2,[5][6][7][8]10,11] cation-p, [4] and ion pair-p interactions [9] for catalysis. [3] Complementary to the more common cation-p interactions on p-basic aromatic surfaces, [4] anion-p interactions occur on p-acidic surfaces.Their existence has been proposed by theoreticians ab it more than ad ecade ago and verified experimentally for the solid, solution, and gas phase.…”