In Situ Synthesis of Gold and Silver Nanoparticles by Using Redox‐Active Amphiphiles and Their Phase Transfer to Organic Solvents

Abstract

An in situ reduction approach to synthesizing gold and silver nanoparticles by using a series of newly designed, redox-active amphiphiles at basic pH is described. These amphiphiles are the conjugates of a fatty acid (e.g., oleic acid, stearic acid, and lauric acid) and a redox-active amino acid (e.g., tryptophan or tyrosine). The amphiphile-coated nanoparticles are then efficiently transferred from water to different nonpolar organic media (such as benzene, toluene, xylene, cyclohexane, and hexane) simply by acid treatment. The phase-transfer process was monitored by UV/visible spectroscopy and transmission electron microscopy, and the results showed that the average particle size and size distribution remain almost unchanged after transferring to the organic media. The anchoring of the amphiphile to the nanoparticle surface was confirmed by FTIR spectroscopy and thermogravimetric analysis. A mechanism is proposed to describe the stability of colloidal Au and Ag nanoparticles formed in situ and their phase transfer to organic solvents. The presence of the amphiphile increases the thermal stability of the colloidal gold nanoparticle conjugates in organic solvents.

Novel Ascorbic Acid Based Ionic Liquids for the In Situ Synthesis of Quasi‐Spherical and Anisotropic Gold Nanostructures in Aqueous Medium

“…[50][51][52][53] This encouraged us to explore the in situ reduction technique further to synthesize MNPs using newly designed redox-active ILs as reducing/stabilizing agents. It is known that ascorbic acid generally exhibits keto-enol tautomerisim, the enol form of which is susceptible to ionization in aqueous solution and has been used as a versatile reducing agent for variety of metal ion precursors to prepare MNPs.…”

Study on the Fluorescence Characteristics of CdTe and Charged Coumarin-Contained Polymer Blending System

“…This showed that the quantity of CdTe QDs in the blending system affected the average particle size of CdTe QDs significantly. Considering all the phenomena above, THF can be inferred as the main factor caused the particle size variation of CdTe QDs 27 . When THF added in the system, no matter C-CPA was added or not added in the system, the particle size of CdTe QDs all changed and as the ratio of THF increasing, the affect increased as well.…”

Doubly Charged Silver Clusters Stabilized by Tryptophan: Ag42+ as an Optical Marker for Monitoring Particle Growth

“…[14] We demonstrate that this hybrid system exhibits an unambiguous optical fingerprint of the doubly charged silver cluster (Ag 4 2+ ) stabilized by a salt-bridge (SB) interaction with the organic moiety. Thus, we propose the use of its optical signature as a marker to monitor early stages of seeding processes for particle growth.…”