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In Situ Synthesis of Gold and Silver Nanoparticles by Using Redox‐Active Amphiphiles and Their Phase Transfer to Organic Solvents
Author(s) -
Si Satyabrata,
Dinda Enakshi,
Mandal Tarun K.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701014
Subject(s) - redox , in situ , silver nanoparticle , amphiphile , colloidal gold , phase (matter) , chemistry , nanoparticle , chemical engineering , nanotechnology , materials science , inorganic chemistry , organic chemistry , copolymer , polymer , engineering
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.