Probing the Surface of Oxide Nanoparticles Using DNP-Enhanced High-Resolution NMR of Quadrupolar Nuclei.

The surfaces of nanomaterials with applications in optoelectronics and catalysis control their physicochemical properties. NMR spectroscopy, enhanced by dynamic nuclear polarization (DNP), is a powerful approach to probe the local environment of spin-1/2 nuclei near surfaces. However, this technique often lacks robustness and resolution for half-integer quadrupolar nuclei, which represent more than 66% of the NMR-active isotopes.

Simple elaboration of drug-SPION nanocapsules (hybridosomes®) by solvent shifting: Effect of the drug molecular structure and concentration.

Drug nanocapsules coated with iron oxide nanoparticles (SPION) were elaborated by the simultaneous nanoprecipitation of the drug and the nanoparticles, through solvent shifting. We examined four drugs: sorafenib, sorafenib tosylate, α-tocopherol and paclitaxel, to cover the cases of molecular solids, ionic solids, and molecular liquids. We first investigated the formation of the drug core in the final mixture of solvents at different concentrations.

Gelation Mechanism Revealed in Organometallic Gels: Prevalence of van der Waals Interactions on Oligomerization by Coordination Chemistry.

Shaping of nanomaterials is a necessary step for their inclusion in electronic devices and batteries. For this purpose, the formulation of a moldable material including these nanomaterials is desirable. Organomineral gels are a very interesting option, since the components of the nanomaterial itself form a gel without the help of a binder.

Nano-Structuration of WO Nanoleaves by Localized Hydrolysis of an Organometallic Zn Precursor: Application to Photocatalytic NO Abatement.

WO is a known photocatalytic metal oxide frequently studied for its depollution properties. However, it suffers from a high recombination rate of the photogenerated electron/holes pair that is detrimental to its performance. In this paper, we present a new chemical method to decorate WO nanoleaves (NLs) with a complementary metal oxide (ZnWO) in order to improve the photocatalytic performance of the composite material for the abatement of 400 ppb NO under mild UV exposure.

Secured Nanosynthesis-Deposition Aerosol Process for Composite Thin Films Incorporating Highly Dispersed Nanoparticles.

Application of nanocomposites in daily life requires not only small nanoparticles (NPs) well dispersed in a matrix, but also a manufacturing process that is mindful of the operator and the environment. Avoiding any exposure to NPs is one such way, and direct liquid reaction-injection (DLRI) aims to fulfill this need. DLRI is based on the controlled in situ synthesis of NPs from the decomposition of suitable organometallic precursors in conditions that are compatible with a pulsed injection mode of an aerosol into a downstream process.

Anisotropic growth of ZnO nanoparticles driven by the structure of amine surfactants: the role of surface dynamics in nanocrystal growth.

Herein, we elucidate the key role of amine surfactants in the controlled anisotropic growth of ZnO nanoparticles that is achieved under mild conditions by organometallic hydrolysis. The structuring influence of alkyl substituents on the nitrogen atom of amines is jointly analyzed theoretically by DFT modeling, and experimentally by multinuclear NMR (H, C and O) spectroscopy. We demonstrate that in initial steps leading to the growth of colloidal ZnO particles, the nature of molecular species that are involved in the solution strongly depends on the structure of the amine surfactant.

Mechanistic insights into the anisotropic growth of ZnO nanoparticles deciphered through 2D size plots and multivariate analysis.

The control and understanding of the nucleation and growth of nano-objects are key points for improving and/or considering the new applications of a given material at the nanoscale. Mastering the morphology is essential as the final properties are drastically affected by the size, shape, and surface structure. Yet, a number of challenges remain, including evidencing and understanding the relationship between the experimental parameters of the synthesis and the shape of the nanoparticles.

Coordination of Ethylamine on Small Silver Clusters: Structural and Topological (ELF, QTAIM) Analyses.

Amine ligands are expected to drive the organization of metallic centers as well as the chemical reactivity of silver clusters early growing during the very first steps of the synthesis of silver nanoparticles an organometallic route. Density functional theory (DFT) computational studies have been performed to characterize the structure, the atomic charge distribution, and the planar two-dimensional (2D)/three-dimensional (3D) relative stability of small-size silver clusters (Ag, 2 ≤ ≤ 7), with or without an ethylamine (EA) ligand coordinated to the Ag clusters. The transition from 2D to 3D structures is shifted from = 7 to 6 in the presence of one EA coordinating ligand, and it is explained from the analysis of the Ag-N and Ag-Ag bond energies.

Radiosensitizing Fe-Au nanocapsules (hybridosomes®) increase survival of GL261 brain tumor-bearing mice treated by radiotherapy.

Glioblastoma remains a cancer for which the effectiveness of treatments has shown little improvement over the last decades. For this pathology, multiple therapies combining resection, chemotherapy and radiotherapy remain the norm. In this context, the use of high-Z nanoparticles such as gold or hafnium to potentiate radiotherapy is attracting more and more attention.

Nanocatalysts for High Selectivity Enyne Cyclization: Oxidative Surface Reorganization of Gold Sub-2-nm Nanoparticle Networks.

Ultrasmall gold nanoparticles (NPs) stabilized in networks by polymantane ligands (diamondoids) were successfully used as precatalysts for highly selective heterogeneous gold-catalyzed dimethyl allyl(propargyl)malonate cyclization to 5-membered conjugated diene. Such reaction usually suffers from selectivity issues with homogeneous catalysts. This control over selectivity further opened the way to one-pot cascade reaction, as illustrated by the 1,6-enyne cycloisomerization-Diels-Alder reaction of dimethyl allyl propargyl malonate with maleic anhydride.

The Hydrogen-Storage Challenge: Nanoparticles for Metal-Catalyzed Ammonia Borane Dehydrogenation.

Dihydrogen is one of the sustainable energy vectors envisioned for the future. However, the rapidly reversible and secure storage of large quantities of hydrogen is still a technological and scientific challenge. In this context, this review proposes a recent state-of-the-art on H production capacities from the dehydrogenation reaction of ammonia borane (and selected related amine-boranes) as a safer solid source of H by hydrolysis (or solvolysis), catalyzed by nanoparticle-based systems.

Effect of nanoparticles on spontaneous Ouzo emulsification.

Particles stabilize fluid interfaces. In particular, oil/water Pickering emulsions undergo limited coalescence, yielding droplets of smaller size as the amount of particles is increased. Herein, we studied the effect of hydrophobic nanoparticles (<10 nm, alkyl-coated) on submicronic droplets (ca 100 nm) formed in an Ouzo system.

Prominence of the Instability of a Stabilizing Agent in the Changes in Physical State of a Hybrid Nanomaterial.

Shaping ability of hybrid nanomaterials is a key point for their further use in devices. It is therefore crucial to control it. To this end, it is necessary that the macroscopic properties of the material remain constant over time.

Topological Analysis of Ag-Ag and Ag-N Interactions in Silver Amidinate Precursor Complexes of Silver Nanoparticles.

A series of silver amidinate complexes has been studied both experimentally and theoretically, in order to investigate the role of the precursor complex in the control of the synthesis of silver nanoparticles via an organometallic route. The replacement of the methyl substituent of the central carbon atom of the amidinate anion by a -butyl group allows for the crystallization of the tetranuclear silver amidinate complex instead of a mixture of di- and trinuclear silver amidinate complexes and , as obtained with a methyl substituent. The relative stabilities and dissociation schemes of various isomeric arrangements of silver atoms in are investigated at the computational DFT level of calculation, depending on the substituents of the amidinate ligand.

Nanocrystal-ligand interactions deciphered: the influence of HSAB and p in the case of luminescent ZnO.

Despite all the efforts made by the scientific community to rationalize the interaction of organic molecules with nanocrystals (Ncs), we are still at the level of the empirical recipe when the material behavior in solution is concerned. In an effort to address this issue, the analysis of the luminescence measurements of ZnO Ncs in the presence of various organic substrates using a Langmuir adsorption model was carried out to determine for the first time the affinity constants and the number of binding sites as well as to rank the interaction strengths of these substrates with regard to ZnO Ncs. The results were confirmed by NMR spectroscopic studies, which, besides, provided a deep understanding of the substrate-ZnO Nc interactions.

Removable Composite Electrode Made of Silver Nanoparticles on Pyrolyzed Photoresist Film for the Electroreduction of 4-Nitrophenol.

Access to removable nanocomposite electrodes for electrosensing of pollutants is of great importance. However, the preparation of reproducible and reliable carbon electrodes decorated with metallic nanoparticles, a prerequisite for trustworthy devices, remains a challenge. Here we describe an innovative and easy method to prepare such electrodes.

The role of alkylamine in the stabilization of CuO nanoparticles as a determinant of the Al/CuO redox reaction.

We report on a new strategy to synthesize Al/CuO nanothermites from commercial Al and ultra-small chemically synthesized CuO nanoparticles coated with alkylamine ligands. These usual ligands stabilize the CuO nanoparticles and prevent them from aggregating, with the goal to enhance the interfacial contact between Al and CuO particles. Using a variety of characterization techniques, including microscopy, spectroscopy, mass spectrometry and calorimetry (ATG/DSC), the structural and chemical evolution of CuO nanoparticles stabilized with alkylamine ligands is analyzed upon heating.

Nonisotropic Self-Assembly of Nanoparticles: From Compact Packing to Functional Aggregates.

Quantum strongly correlated systems that exhibit interesting features in condensed matter physics often need an unachievable temperature or pressure range in classical materials. One solution is to introduce a scaling factor, namely, the lattice parameter. Synthetic heterostructures named superlattices or supracrystals are synthesized by the assembling of colloidal atoms.

Multinuclear solid-state NMR study: a powerful tool for understanding the structure of ZnO hybrid nanoparticles.

Characterization of hybrid materials is crucial for gaining an in-depth understanding of nano-objects. Here, it is evidenced that the use of multinuclear 1H, 2H, 13C, 15N, 67Zn and 17O MAS NMR spectroscopy is a very powerful approach to acquire both structural and dynamic information on hybrid ZnO nanomaterials prepared from an organometallic approach. Not only is the coordination mode of the organic part onto the inorganic surface evidenced but also important information about the dynamics of the organic capping molecules and some particularities of the nanocrystal structure itself are obtained.

Electro-click construction of hybrid nanocapsule films with triggered delivery properties.

Hollow nanocapsules (named Hybridosomes®) possessing a polymer/nanoparticle shell were used to covalently construct hybrid films in a one-pot fashion. The alkyne bearing organic/inorganic Hybridosomes® were reticulated with azide bearing homobifunctional polyethyleneglycol (PEG) linkers, by using an electro-click reaction on F-SnO (FTO) electrodes. The coatings were obtained by promoting the Cu(i)-catalyzed click reaction between alkyne and azide moieties in the vicinity of the electrode by the electrochemical generation of Cu(i) ions.

Organometallic Synthesis of CuO Nanoparticles: Application in Low-Temperature CO Detection.

A metal-organic approach has been employed for the preparation of anisotropic CuO nanoparticles. These nanostructures have been characterized by transmission and high resolution transmission electron microscopy, field-emission scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The CuO nanoparticles have been deposited as gas-sensitive layers on miniaturized silicon devices.