Discrete functional gold nanoparticles: hydrogen bond-assisted synthesis, magnetic purification, supramolecular dimer and trimer formation.
Amine monofunctional gold nanoparticles (1-AuNPs) were synthesized by employing a solid-supported technique and pH-switchable pseudorotaxane formation. Purification was repeatedly facilitated using crown ether peripherally coated superparamagnetic iron oxide microspheres to yield the monofunctional gold nanoparticles in excellent yield. The product and its related intermediate superstructures were characterized by IR and X-ray photoelectron spectroscopies. Novel supramolecular dimers and trimers were prepared by titrating the 1-AuNPs with bisDB24C8 and trisDB24C8 at different ratios. UV/visible absorption spectroscopic analyses of the supramolecular dimer and trimer solutions, which were formed by mixing their separate components in different ratios, indicated the gradual appearance of two distinct plasmonic resonance bands at 620 and approximately 700 nm. Furthermore, TEM images of the dimers revealed a significant amount of dimer pairs on the surface, while the TEM images of the trimers demonstrated the presence of both dimers and trimers. The trimers appeared as triangular or near-linear shapes.
Chak
Chun-Pong
CP
Center of Novel Functional Molecules, Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
Xuan
Shouhu
S
Mendes
Paula M
PM
Yu
Jimmy C
JC
Cheng
Christopher H K
CH
Leung
Ken Cham-Fai
KC
D001697:Biomedical and Dental Materials; D006046:Gold / Q000737:chemistry*; D006860:Hydrogen Bonding; D008280:Magnetics; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure
D001697:Biomedical and Dental Materials; D006046:Gold