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Nanostructures are considered as chemical systems of high potential owing to their unusual properties at the interface of those of molecular species and bulk metals. Consequently, they are promising candidates for application in different domains such as catalysis, magnetism, medicine, opto-electronics or sensors. The control of the characteristics of nanostructures is a fundamental prerequisite if one envisages exploring their physical or chemical properties since they vary dramatically with size, shape and surface state. Thus, the development of efficient methods leading to reproducible nanostructures is presently one of the main objectives in the nanochemistry community. Although organometallic chemistry has been early involved, it arises only marginally in the field. Nevertheless, the concepts and techniques of organometallic chemistry appear to be well-adapted for the growth of well-controlled nanostructures. This will be discussed through recent advances in the synthesis of metal and metal oxide nanoparticles in terms of size dispersion, chemical composition, surface state, shape or organization, pointing out the role of ligands. Moreover their characterization at a molecular level and the development of their chemical/physical properties towards applications will be described. This review reflects more than 20 years of efforts of our team to achieve these goals. [ABSTRACT FROM AUTHOR]

Production of hydrogen from a renewable source that is water requires the development of sustainable catalytic processes. This implies, among others, developing efficient catalytic materials from abundant and low-cost resources and investigating their performance, especially in the oxidation of water as this half-reaction is the bottleneck of the water splitting process. For this purpose, NiFe-based nanoparticles with sizes ca. 3–4 nm have been synthesized by an organometallic approach and characterized by complementary techniques (WAXS, TEM, STEM-HAADF, EDX, XPS, and ATR-FTIR). They display a Ni core and a mixed Ni–Fe oxide shell. Once deposited onto FTO electrodes, they have been assessed in the electrocatalytic oxygen evolution reaction under alkaline conditions. Three different Ni/Fe ratios (2/1, 1/1 and 1/9) have been studied in comparison with their monometallic counterparts. The Ni2Fe1 nanocatalyst displayed the lowest overpotential (320 mV at j = 10 mA cm−2) as well as excellent stability over 16 h. [ABSTRACT FROM AUTHOR]

New pyridine containing triAza; 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (PCTA) ligands presenting pendant carboxylic acid or alcohol functions have been synthesized and used to form diaqua Gd(III) complexes, which have been immobilized onto dense silica nanoparticles. Cytotoxicity studies of these complexes (free or immobilized on the nanoparticles) on normal 1BR3G cells and cancerous HCT 116 cells indicated a dependence on the pendant chemical group for the free complexes. However, this effect disappeared once the complexes were immobilized on the surface of the nanoparticles, leading to non-toxic nanomaterials. The interest of these complexes (free or immobilized on dense silica nanoparticles) as contrast agents in magnetic resonance imaging (MRI) has been evaluated in comparison with DOTAREM® by recording their nuclear magnetic resonance dispersion (NMRD) profiles, measuring their transversal and longitudinal relaxivities as well as recording images on phantoms at 37 °C. This study has evidenced the high potential of these complexes: first it suggested the possibility to reduce the dose to be injected by a factor of 10, second it evidenced their high efficiency in high field T1-weighted MRI (9.4 T), the key towards images of higher resolution and shorter acquisition times. [ABSTRACT FROM AUTHOR]

Phosphonic acid derivatives are suitable compounds for controlling the surface properties of materials and nanomaterials. Here, we present for the first time the use of alkyl phosphonic acid ligands to transfer into water zero-valent iron nanoparticles (FeNP) synthesized by an organometallic approach. The transfer takes place with the formation of an oxide layer at the surface of the iron nanoparticles, beneficial for the coordination of the alkyl phosphonic acid ligands. The nanoparticles are highly soluble in water and present a core–shell structure, with a monocrystalline body-centered cubic iron core of ca. 10 nm in size surrounded by a spinel oxide shell of ca. 2 nm thickness. These hydrophilic nanoparticles display excellent structural stability, magnetization still reaching 70% of that of bulk iron, and a transversal relaxivity r2 of 335 mM−1 s−1 which give them high potential for biomedical applications. [ABSTRACT FROM AUTHOR]

Enhancement of the thermoelectric properties of bismuth due to size reduction has prompted a large body of studies and recent interest in the nanochemistry of this material. The size control at the nanometer scale is complicated because of bismuth's low melting point and little known surface chemistry. We report herein an efficient synthetic method producing bismuth nanoparticles (Bi NPs) of sizes below 10 nm, and of rhombohedral structure based on transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) analysis. The nature and dynamics of the ligands at their surface have been investigated by infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectroscopy. We demonstrate that alkynyl ligands, seldom used in nanochemistry, efficiently coordinate at the surface and afford stable Bi NPs that can be easily purified, leading to powders with high bismuth payload which can be redispersed into stable colloidal solutions. [ABSTRACT FROM AUTHOR]