Colloidal nanoparticles are being intensely pursued in current nanoscience research. Nanochemists are often frustrated by the well-known fact that no two nanoparticles are the same, which precludes the deep understanding of many fundamental properties of colloidal nanoparticles in which the total structures (core plus surface) must be known. Therefore, controlling nanoparticles with atomic precision and solving their total structures have long been major dreams for nanochemists. Recently, these goals are partially fulfilled in the case of gold nanoparticles, at least in the ultrasmall size regime (1–3 nm in diameter, often called nanoclusters). This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of atomic structures, and unique physical and chemical properties of atomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles (such as the s...

Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles: Fundamentals and Opportunities

Alloy negative electrodes for Li-ion batteries.

Atomically precise pieces of matter of nanometer dimensions composed of noble metals are new categories of materials with many unusual properties. Over 100 molecules of this kind with formulas such as Au25(SR)18, Au38(SR)24, and Au102(SR)44 as well as Ag25(SR)18, Ag29(S2R)12, and Ag44(SR)30 (often with a few counterions to compensate charges) are known now. They can be made reproducibly with robust synthetic protocols, resulting in colored solutions, yielding powders or diffractable crystals. They are distinctly different from nanoparticles in their spectroscopic properties such as optical absorption and emission, showing well-defined features, just like molecules. They show isotopically resolved molecular ion peaks in mass spectra and provide diverse information when examined through multiple instrumental methods. Most important of these properties is luminescence, often in the visible–near-infrared window, useful in biological applications. Luminescence in the visible region, especially by clusters prot...

Atomically Precise Clusters of Noble Metals: Emerging Link between Atoms and Nanoparticles

https://physique.cuso.ch/fileadmin/physique/document/2005_vanStokkum_lecturenotes.pdf

Global and target analysis of time-resolved spectra

Metal or metal oxide nanoparticles possess unique features compared to equivalent larger-scale materials. For applications, it is often necessary to stabilize or functionalize such nanoparticles. Thus, modification of the surface of nanoparticles is an important chemical challenge. In this survey, various possibilities are discussed how nanoparticles can be protected by organic ligands and how these ligands can be used to introduce functionalities. The preparative possibilities include grafting of an already functionalized ligand on the nanoparticle surface, exchanging part or all existing ligands on the nanoparticle surface, or grafting of a ligand on a nanoparticle followed by modification by organic chemical reactions.

Surface modification and functionalization of metal and metal oxide nanoparticles by organic ligands

The protein–gold nanoparticle bioconjugates are playing an important role in the studies of biological systems. The nature of the interaction and the magnitude of the binding affinity together with the conformational changes in the protein upon binding are the most addressed topics in relation to the uses of the bioconjugates in different organisms. In this work, we study the human serum albumin (HSA) protein–gold nanoparticle (AuNP) interactions focusing on the nature of the gold nanoparticle surface modification. We have found that the interactions of the HSA with the AuNPs are mainly electrostatic and that the concentration of protein necessary to stabilize the conjugates decreases when the overall negative charge on the nanoparticle surface increases. The changes in the localized surface plasmon resonance (LSPR) signals of the gold nanoparticles (13 nm diameter) are used to determine the number of protein molecules necessary to stabilize the conjugates in a high ionic strength medium. Fluorescence spe...

Role of the Functionalization of the Gold Nanoparticle Surface on the Formation of Bioconjugates with Human Serum Albumin

Derivation and experimental verification of approximate explicit equations in differential pulse polarography

6-Mercaptopurine-coated gold nanoparticles (6MP-AuNPs) have been prepared by modification of the nanoparticle surface with 6MP upon displacement of the protective layer of citrate anions. The modification has been studied by UV-vis and FTIR spectroscopies. A study of the stability of these 6MP-AuNPs in aqueous solutions as a function of ionic strength and pH has shown the importance of the charges on the stabilization. The protonation of N9 of the 6MP molecules brings about a sudden flocculation phenomenon. However, the flocculation is reversible upon changing the pH to values where the molecules become newly charged. Evidence of the competence between the interaction of capping solvent molecules and the attractive forces between particles is also shown in this paper.

Stabilization of gold nanoparticles by 6-mercaptopurine monolayers. Effects of the solvent properties.

Atomistic molecular dynamics calculations of self-assembled monolayers of alkanethiol molecules on gold nanoparticles are carried out to determine the surface per ligand molecule as a function of the size. The molecular footprint is determined by calculating the surface tension starting from its thermodynamic definition in the canonical ensemble. We use the method of Chiu et al. (Chiu, C. C. et al. J. Chem. Phys. 2010, 132, 054706) that makes use of a parametric dependence on the system size of the potential energy between the gold surface and the ligand molecules. The role of the different groups in the molecule in the surface tension is studied. An analysis of the dependence of the surface per thiol molecule on the molecular length is carried out showing that, for molecules larger than hexanethiol, this value is independent of the number of carbon groups in the molecule. The surface occupied per molecule on spherical nanoparticles as a function of the curvature is obtained, and the method is applied to ...

A Molecular Dynamics Study of the Surfactant Surface Density of Alkanethiol Self-Assembled Monolayers on Gold Nanoparticles as a Function of the Radius

Manuel Blázquez

Papers

Role of the Functionalization of the Gold Nanoparticle Surface on the Formation of Bioconjugates with Human Serum Albumin

Derivation and experimental verification of approximate explicit equations in differential pulse polarography

Stabilization of gold nanoparticles by 6-mercaptopurine monolayers. Effects of the solvent properties.

A Molecular Dynamics Study of the Surfactant Surface Density of Alkanethiol Self-Assembled Monolayers on Gold Nanoparticles as a Function of the Radius

A voltammetric study of 6-mercaptopurine monolayers on polycrystalline gold electrodes