Self-Organization of Au Nanoparticles Protected by 2,6-Bis(1‘-(8-thiooctyl)benzimidazol-2-yl)pyridine

Teranishi, Toshiharu; Haga, Masa‐aki; Shiozawa, Yoichi; Miyake, Mikio

doi:10.1021/ja000031u

Cited by 81 publications

(56 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The strategy adopted here is to tune these key steps simultaneously, and strictly creates a single crystalline nanowire with high-aspect ratio and small diameter in a short reaction time. The important roles of adsorbent (e.g., NaI) on specific crystal face [19,23] and solvent environment (e.g., polarity) [23,34] are demonstrated in order to achieve controlled anisotropic shape, in addition to specific organic protective agents [35]. There are two critical strategies in the present preparation procedures.…”

Section: Facile Preparation Of Pt Nanowire Without Templatementioning

confidence: 99%

Shape and Size Controlled Pt Nanocrystals as Novel Model Catalysts

Miyake

Miyabayashi

2011

Catal Surv Asia

Self Cite

View full text Add to dashboard Cite

A tremendous development of nanotechnology enabled us to prepare precisely structure-controlled nanocrystals (NCs). Recently, such structure controlled NCs have been applied as model catalysts with controlled active sites to evaluate reaction mechanisms. Here, we review our recent works on preparation of shape controlled Pt NCs, such as cube and wire, and on application as model catalysts for olefin hydrogenation to assess active Pt sites. A hydrogen reduction method of Pt(II) ion was adopted in an aqueous phase to prepare Pt cube in the presence of shape forming agent (NaI) and organic protective agent (sodium polyacrylate or sodium succinate). We succeed to prepare Pt cube with high size and shape selectivity, followed by very small Pt cube of less than 3 nm. Such simultaneous control of both size and shape of Pt NCs has been successfully achieved by the sophisticated tuning of multiple conditions for the growth kinetics of Pt nuclei during hydrogen reduction of PtCl 4 2-in aq. N-, N-dimethylformamide (DMF) solution. The key strategy is to produce small Pt nuclei and to avoid the excessive growth of Pt nuclei, in conjunction with face selective adsorption of anionic protective and shape-forming agents by the control of solvent system. For the preparation of Pt nanowires with high anisotropy, template-assisted methods have been usually used. We have developed facile liquid phase preparation method at room temperature in air without any template. The key factors of the method are: firstly, to use aqueous organic solvent system to control solvent polarity; secondly, to use co-solvent DMF as shape forming agent; thirdly, to use excess NaBH 4 as a stabilizer of Pt nuclei to prevent formation of conventional particles. Single-crystalline Pt nanowires of 2 nm diameter and more than micron length were easily obtained by the reduction of Pt(IV) with excess NaBH 4 in water-DMF-toluene solution (1:8:5 volume ratio) in a short reaction period of 3 h. Then, we have applied shape-controlled Pt NCs protected with PAA prepared by our original methods, such as cube, tetrahedron and wire, as model catalysts for olefin (cis-and trans-stilbenes) hydrogenation in ethanol to evaluate the active facet of Pt catalysts; e.g., Pt(111) or Pt(100). The estimated TOF values for the hydrogenation of cis-and trans-stilbene decreased in the order: cube [ cuboctahedron [ tetrahedron * nanowire. This tendency indicates that Pt(100) show high activity compared with Pt(111). The result is compatible with measurement of XPS and Raman spectra, suggesting strong adsorption of reactant on Pt(100). Hydrogenation of olefins (1-hexene and cyclohexene) has been carried out over Pt cubes with different sizes (8.2-10.1 nm) as catalysts to get information about active sites of Pt catalysts, e.g., flat facet or edge/corner atoms. The results of similar TOF values among Pt cubes with different sizes imply that the active sites are flat facets.

show abstract

Section: Facile Preparation Of Pt Nanowire Without Templatementioning

confidence: 99%

Shape and Size Controlled Pt Nanocrystals as Novel Model Catalysts

Miyake

Miyabayashi

2011

Catal Surv Asia

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is interesting to point out that using larger particles [15] or other protective ligands inducing the weak interligand interaction [16] could resolve this problem.…”

Section: Area-selective Deposition Of Nanomaterials By Lsmcdmentioning

confidence: 99%

A new approach to molecular devices using SAMs, LSMCD and Cat-CVD

Nishikawa

Mitani

2003

Science and Technology of Advanced Materials

View full text Add to dashboard Cite

This paper proposes a new technology for the fabrication of molecular devices using nanotechnology based on liquid and surface sciences recently developed, such as the direct patterning of solid surfaces using the difference of hydrophobic and hydrophilic properties of selfassembled mono-layers and self-assembly films of metal nanoparticles, the fine fabrication of films by the method of Liquid Source Misted Chemical Deposition, and the Langmuir-Blodgett self-assembly films. In these liquid-based technologies, various kinds of organic compounds in solutions, including biological systems, can be used as functional materials in molecular devices. In addition, it has been found that the insulating inorganic films obtained by catalytic chemical vapor deposition are quite effective in the protection of molecular devices against water and/or oxygen. We confirm, from the experimental results presented in this report, that this new approach is practically promising in future. q

show abstract

“…Gold clusters have been prepared by the in situ reduction of HAuCl 4´4 H 2 O with KBH 4 in the presence of 2,6-bis(1'-(8-thiooctyl)benzimidazol-2-yl)pyridine [60]. The latter covalently attaches to the gold cluster surface exposing benzimidazole and pyridine groups to the solution.…”

Section: P±p Interactionsmentioning

confidence: 99%

Layer‐By‐Layer Self‐Assembly of Metal Nanoparticles on Planar Substrates: Fabrication and Properties

Cassagneau

2003

Colloids and Colloid Assemblies

View full text Add to dashboard Cite

Self-assembly processes involve non-covalent interactions based on electrostatics, charge-transfer, hydrophilicity-hydrophobicity, H-bonding, chelation, metal coordination, p±p coupling, etc. The term ªselfº in self-assembly accounts for the fact that each interactive building block unit carries information that inherently defines its binding properties and is relevant enough to determine a spontaneous interaction at a receptive site or surface. The building block under consideration can be any molecule, ion, cluster, particle, polymer, etc., that participates in the film growth. The idea of using the binding capabilities (especially through electrostatic interactions) of micrometric objects to sequentially build-up structures on a support was first presented in 1966 [1]. Since then micrometer-sized objects have been designed and functionalized in such a way that they can self-organize into complex patterns [2]. Sequential electrostatic self-assembly was further extended to the build-up of biphosphonate anions with polycationic species (1988) [3] and to the adsorption of polyelectrolyte multilayers (1991) [4] as an alternative to the Langmuir-Blodgett monolayer transfer technique for film formation. The layer-bylayer assembly technique relies on the alternate immersion of a derivatized substrate, S, into a solution of building blocks A and a solution of building blocks B, both bearing chemical functions directing their mutual spontaneous interaction. Upon repeating adsorption cycles a periodic film grows at the substrate surface, S±(AB) n . The consecutive adsorption of particles with a binder on a planar substrate defines layers whose properties integrate over the entire film. The sequences of layering along with the choice of building blocks to be used determine a certain synergy between the layers. The versatility of this technique is not limited to the build-up of binary systems, and complex arrangements can be designed to form three-dimensional nanostructures with interesting properties [5]. Very often one building block is used as an inert binder to facilitate the adsorption of an element that brings the desired functionality upon assembly (Fig. 13.1). A given functionality is not only ªpackagedº within a discrete entity, say a nanoparticle, with specific magnetic, optical or electrical properties, but also localized within a three-dimensional nanostructure. Ideally, the layer-by-layer self-assembly

show abstract

Self-Organization of Au Nanoparticles Protected by 2,6-Bis(1‘-(8-thiooctyl)benzimidazol-2-yl)pyridine

Cited by 81 publications

References 47 publications

Shape and Size Controlled Pt Nanocrystals as Novel Model Catalysts

Shape and Size Controlled Pt Nanocrystals as Novel Model Catalysts

A new approach to molecular devices using SAMs, LSMCD and Cat-CVD

Layer‐By‐Layer Self‐Assembly of Metal Nanoparticles on Planar Substrates: Fabrication and Properties

Contact Info

Product

Resources

About