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Toshiharu Teranishi

Publications and source records attributed to Toshiharu Teranishi.

9 recordsLinked to original sources
PubMed2006

Self-assembly of small gold nanoparticles through interligand interaction.

Stable and monodisperse Au nanoparticles smaller than 2 nm are easily prepared by the reduction of HAuCl(4) x 4H(2)O in DMF/H(2)O in the presence of a series of bidentate ligands, 2,6-bis(1'-(n-thioalkyl)benzimidazol-2-yl)pyridine (TC(n)BIP, n = 3, 6, 8, 10, 12). The TC(n)BIP ligands afford stronger coordination ability than alkanethiols due to their bidentate nature. These small nanoparticles form hexagonal close-packed (hcp) two-dimensional (2D) superlattices with tunable interparticle spacings (from 1.2 to 2.5 nm), produced by changing the length of the ligand at both the hydrophobic amorphous carbon and the air-water interface. Long-range-ordered hcp 2D superlattices were fabricated through the cleavage and construction of interligand pi-pi interactions formed via an annealing process at the air-water interface.

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PubMed2006

One-pot synthesis of large FePt nanoparticles from metal salts and their thermal stability.

One-pot synthesis of FePt nanoparticles larger than 5 nm with controlled composition has been developed by the polyol reduction of platinum acetylacetonate and iron acetylacetonate in excess ligands. The obtained large FePt nanoparticles (6.1 +/- 0.6 nm Fe36Pt64, 5.8 +/- 0.7 nm Fe44Pt56, and 5.1 +/- 0.7 nm Fe49Pt51 nanoparticles) were thermally more stable than the small ones and were hard to coalesce in the in-plane direction for their 2D superlattice.

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PubMed2006

Single electron on a nanodot in a double-barrier tunneling structure observed by noncontact atomic-force spectroscopy.

A single electron has been observed on a nanodot in a double-barrier tunneling structure by noncontact atomic-force microscopy at fixed separation. Frequency shift-voltage dependence of an Au-coated cantilever/vacuum/1-decanethiol protected Au nanodot/1-octanethiol self-assembled monolayer/Au substrate structure deviates from the theoretical parabolic curve, which is attributed to the change in the number of quantized electrons on the Au nanodot caused by the Coulomb blockade phenomena.

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PubMed2005

Large-scale synthesis of thiolated Au25 clusters via ligand exchange reactions of phosphine-stabilized Au11 clusters.

Phosphine-stabilized Au11 clusters in chloroform were reacted with glutathione (GSH) in water under a nitrogen atmosphere. The resulting Au:SG clusters exhibit an optical absorption spectrum similar to that of Au25(SG)18, which was isolated as one of the major products from chemically prepared Au:SG clusters (Negishi, Y. et al. J. Am. Chem. Soc. 2005, 127, 5261). Rigorous characterization by optical spectroscopy, electrospray ionization mass spectrometry, and polyacrylamide gel electrophoresis confirms that the Au25(SG)18 clusters were selectively obtained on the sub-100 mg scale by ligand exchange reaction under aerobic conditions. The ligand exchange strategy offers a practical and convenient method of synthesizing thiolated Au25 clusters on a large scale.

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PubMed2004

Nanoacorns: anisotropically phase-segregated CoPd sulfide nanoparticles.

The anisotropically phase-segregated CoPd sulfide nanoparticles, named "CoPd nanoacorns", were spontaneously generated by reducing the corresponding metal precursors with 1,2-hexadecanediol in the presence of various alkanethiols. The CoPd nanoacorn consisting of crystalline Co9S8 and amorphous PdSx phases with the Co9S8 (001) plane at their interface was found to spontaneously form through the anisotropic growth of the Co9S8 phase after the generation of PdSx nanoparticles.

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PubMed2003

Formation of low-symmetric 2D superlattices of gold nanoparticles through surface modification by acid-base interaction.

In the present work, a novel method was developed for the fabrication of 2D superlattices with different symmetries. Same-surface amino-functionalized Au nanoparticles as building blocks were self-assembled to form different 2D superlattices using surface modification with organic acids. The 2D superlattices of quasi-honeycomb and square structures were obtained by neutralizing amino-functionalized Au nanoparticles with 1,3,5-tribenzenecarboxylic acid and acetic acid, respectively. These results strongly suggest that the different types of 2D or 3D superlattices can be constructed by simple addition of proper acid to nanoparticles functionalized with amino groups. This method will allow us to obtain various desired metal superlattices without fully synthesizing the ligands.

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PubMed2003

Directed self-assembly of two kinds of nanoparticles utilizing monolayer films of diblock copolymer micelles.

We demonstrated a self-assembly of two different kinds of nanoparticles simultaneously directed on a monolayer film of diblock copolymer micelles via physical and chemical arrangements. We first incorporated gold nanoparticles physically around the micelles of a monolayer film of PS-PVP micelles having a short-range hexagonal order. Iron oxide nanoparticles were then synthesized chemically in the PVP core area of the ordered micelles, resulting in a mosaic nanopattern of magnetic iron oxide nanoparticles surrounded by metallic gold nanoparticles. Thus, we were able to direct two kinds of nanoparticles to self-assemble in the specific positions as an example of controlled fabrication of nanometer-sized building blocks.

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PubMed2002

Planar array of 1D gold nanoparticles on ridge-and-valley structured carbon.

For fabrication of a planar array of 1D chains of gold nanoparticles prepared by a chemical process, the faceted (110) planes of sodium chloride crystals were used as templates to produce nanoscale ridge-and-valley structured carbon layers by a vacuum process. When these carbon layers loaded on copper grids were dipped in toluene solution of 3.4 nm gold nanoparticles followed by natural dry, a planar array of 1D chains of gold nanoparticles were formed on carbon layers, where the nanoparticles were immobilized predominantly in valleys and partly on ridges of carbon layers.

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