Gold nanoparticle assemblies stabilized by bis(phthalocyaninato)lanthanide(III) complexes through van der Waals interactions

Yuki Noda,Tomoyuki Akutagawa,Shin-Ichiro Noro,Takayoshi Nakamura

doi:10.1038/srep03758

Yuki Noda, Tomoyuki Akutagawa + Show 2 more

Open Access

https://doi.org/10.1038/srep03758

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Journal: Scientific Reports	Publication Date: Jan 20, 2014
Citations: 21	License type: CC BY 3.0

Affiliation: Hokkaido University, Tohoku University

Abstract

Gold nanoparticle assemblies possess diverse application potential, ranging from industrial nanotechnology to medical biotechnology. Because the structures and properties of assemblies are directly affected by the stabilization mechanism between the organic molecules serving as protecting ligands and the gold nanoparticle surface, it is crucial to find and investigate new stabilization mechanisms. Here, we report that π-conjugated phthalocyanine rings can serve as stabilizing ligands for gold nanoparticles. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato)terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. AC magnetic measurements and the electron-transport properties of the assemblies give direct evidence that the phthalocyanines are isolated from each other. Each nanoparticle shows weak electronic coupling despite the short internanoparticle distance (~1 nm), suggesting Efros–Shklovskii-type variable-range hopping and collective single-electron tunnelling behaviours.

Highlights

Such weak electronic interactions within the assembly prevented the disappearance of plasmonic or semiconducting properties[19]. This implies that the LnPc2–AuNP assemblies provide the opportunity to control the physical properties by molecular design rather than by the arrangement of nanoparticle arrays. These gold nanoparticle assemblies will open up new applications such as the realization of the biomimesis of an artificial neural network brain whose elements are integrated through weak interactions
The neutral electronic state was confirmed by the blocking temperature (TB) value, which was estimated by the alternating current (AC) magnetic properties
The localization length a demonstrates the weak interaction between a gold nanoparticle and the complexes

Summary

MATERIALS METHODOLOGY MAGNETIC PROPERTIES AND

Gold nanoparticle assemblies stabilized by bis(phthalocyaninato)lanthanide(III) complexes through van der Waals interactions. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato)terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. By employing LnPc2 complexes as a protecting ligand for gold nanoparticles, internanoparticle distance was sufficiently close while the electronic nanoparticle-nanoparticle and nanoparticle-complex interactions remained weak Such weak electronic interactions within the assembly prevented the disappearance of plasmonic or semiconducting properties[19]. This implies that the LnPc2–AuNP assemblies provide the opportunity to control the physical properties by molecular design rather than by the arrangement of nanoparticle arrays. These gold nanoparticle assemblies will open up new applications such as the realization of the biomimesis of an artificial neural network brain whose elements are integrated through weak interactions

Results

Discussion

Methods