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Spin crossover (SCO) iron (II) coordination compounds in the form of nanohybrid SCO@SiO 2 particles were prepared using a reverse micelles technique based on the TritonX-100/cyclohexane/water ternary system. Tetraethyl orthosilicate (TEOS) acts as precursor of both the SiF 6 2- counter-anion and SiO 2 to obtain Fe(NH 2 trz) 3 (BF 4 ) 2-x (SiF 6 ) x/2 @SiO 2 nanoparticles with different sizes and morphologies while modifying the TEOS concentration and reaction time. The adjustable mixed-anion strategy leads to a range of quite scarce abrupt spin crossover behaviors with hysteresis just above room temperature (ca. 293 K), which is very promising for the integration of these materials into functional devices.

Herein, we achieved spontaneous emulsification of organometallic precursors to elaborate subμm metal nanocapsules after interfacial reduction. Depending on the proportion of the three components, water, solvent, and the metal precursor, either thermodynamically stable "surfactant-free microemulsions" (SFME) or metastable Ouzo emulsions are formed. We investigated the catalytic transition metals Au, Pd, and Pt, individually or combined, and stabilized by various ligands. Upon reduction of the precursors, either shells of discrete nanoparticles (NPs) or continuous shells were obtained, for the SFME and Ouzo emulsions, respectively. The Au/Pd mixed emulsions lead to a unique structural morphology, in which the Au-Pd nanoparticles are embedded in a continuous submicronic metal shell. The AuNPs are available to grow larger particles within the NP shell using a seeded growth approach. The water-stable and surfactant-free nanocapsules are appealing as catalysts, and, as such, were evaluated for the hydrolysis of ammonia-borane as a promising catalytic strategy for H 2 release from an H-high-content storage material. This work establishes for the first time a genuine activity of water-compatible gold colloids for this reaction.

WO 3 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 3 nanoleaves (NLs) with a complementary metal oxide (ZnWO 4 ) in order to improve the photocatalytic performance of the composite material for the abatement of 400 ppb NO 2 under mild UV exposure. Our strategy was to synthesize WO 3 ·2H 2 O nanoleaves, then, to expose them, in water-free organic solution, to an organometallic precursor of Zn(Cy) 2 . A structural water molecule from WO 3 ·2H 2 O spontaneously decomposes Zn(Cy) 2 and induces the formation of the ZnO@WO 3 ·H 2 O nanocomposite. The material was characterized by electronic microscopy (SEM, TEM), TGA, XRD, Raman and solid NMR spectroscopies. A simple thermal treatment under air at 500 °C affords the ZnWO 4 @WO 3 nanocomposite. The resulting material, additionally decorated with 1% wt. Au, presents a remarkable increase (+166%) in the photocatalytic abatement of NO 2 under UV compared to the pristine WO 3 NLs. This synthesis method paves the way to the versatile preparation of a wide range of MOx@WO 3 nanocomposites (MOx = metal oxide).

The decoration of carbon nanotubes (CNTs) by metal nanoparticles (NPs) combines the advantages of a high specific surface material with catalytic properties of metal nanocrystals. Little work has been devoted to the decoration of CNTs with copper NPs, and no evidence of copper atomic decoration of CNTs has shown up until now. Herein, we demonstrate that the strong acidic oxidation of double-walled CNTs (dwCNTs) is very efficient for the decoration of the carbon surface by copper NPs and atoms. This treatment severely degraded the CNT walls and generated a large amount of disordered sp 3 carbon. This amorphous carbon film bears many chemically active functions like carboxyl and hydroxyl ones. In such conditions, the CNT walls behave as very efficient ligands for the stabilization of copper obtained by the thermolysis of the mesityl precursor in organic solution under mild dihydrogen pressure. In addition to copper NPs, we evidenced the presence of a regular coverage with copper atoms over the dwCNTs. This nanocomposite catalyzes the quantitative synthesis of propargylamines via one A 3 -type coupling reaction. Five consecutive catalytic cycles with 100% yield could be performed with no loss of activity, and the combination of Cu supported on dwCNTs allows a facile recycling of the catalytic material.

A small water-soluble phosphorus-containing dendrimer was engineered for the complexation of gold(I) and for its reduction under mild conditions. Gold nanoparticles were obtained as colloidal suspensions simply and only when the powdered form of this dendrimer was dissolved in water, as shown by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analyses. The dendrimers acted simultaneously as mild reducers and as nanoreactors, favoring the self-assembly of gold atoms and promoting the growth and stabilization of isolated gold nanoparticles. Thus, an unprecedented method for the synthesis of colloidal suspensions of water-soluble gold nanoparticles was proposed in this work., (Copyright © 2020, Gottis et al.; licensee Beilstein-Institut.)

A procedure that enabled rational access to the first example of hybrid material made of NPs grown within a H-bonded framework is reported. To avoid competitive reactions with the framework units, the metal precursor was chemically trapped in the porous structure and subsequently photo-reduced to afford the hybrid material Ag@SPA-2, which consists of Ag NPs of nanometric sizes (<15 nm) homogeneously distributed in the crystals of the host material. In a subsequent step, taking advantage of the porous matrix the silver NPs have been transformed in situ to Ag 2 S NP by simple infiltration of H 2 S. The supramolecular network is shown to play an important role in stabilizing the inorganic nanomaterials and thus in controlling their growth., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This study investigates the non-covalent coating of cobalt magnetic nanoparticles (MNPs) involving a graphene surface with pyrene-tagged dendritic poly(vinylidene fluoride) (PVDF). Dendrimers bearing a pyrene moiety were selected to play the role of spacers between the graphene surface of the MNPs and the PVDF chains, the pyrene unit being expected to interact with the surface of the MNPs. The pyrene-tagged dendritic spacer 11 decorated with ten acetylenic units was prepared and fully characterized. Azido-functionalized PVDF chains were then grafted onto each branch of the dendrimer using Huisgen's [3+2] cycloaddition reaction. Next, the association of the resulting pyrene-tagged dendritic PVDF 13 with commercially available Co/C MNPs by π-stacking interactions was studied by fluorescence spectroscopy. Evaluated were the stability of the π-stacking interactions when the temperature increased and the reversibility of the process when the temperature decreased. Also, hybrid MNPs were prepared from pyrene-tagged dendrimers decorated either with acetylenic functions (11) or with PVDF branches (13), and they were characterized by transmission electron microscopy and comparative elemental analysis was carried out with naked MNPs., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

With the ever increasing miniaturization in microelectronic devices, new deposition techniques are required to form high-purity metal oxide layers. Herein, we report a liquid route to specifically produce thin and conformal amorphous manganese oxide layers on silicon substrate, which can be transformed into a manganese silicate layer. The undesired insertion of carbon into the functional layers is avoided through a solution metal-organic chemistry approach named Solution Layer Deposition (SLD). The growth of a pure manganese oxide film by SLD takes place through the decoordination of ligands from a metal-organic complex in mild conditions, and coordination of the resulting metal atoms on a silica surface. The mechanism of this chemical liquid route has been elucidated by solid-state (29) Si MAS NMR, XPS, SIMS, and HRTEM., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Pure and highly crystalline γ-Fe2O3 nanocrystals (NCs) are obtained when hydrolysis and oxidation of a Fe(II) organometallic precursor are performed in successive steps. Their synthesis in pure alkylamine leads to NCs of about 6 nm. In aqueous solutions of poly(vinyl)pyrrolidone, such pristine NCs form aggregates of about 150 nm that exhibit a high transversal relaxivity (r2 =466 mM(-1) s(-1)) about four times higher than that of a commercial Feridex magnetic resonance imaging (MRI) contrast agent. Consequently, they provide a significant decrease in the NMR signal at very short echo time (8 ms), which is of paramount importance in clinical practice because of the reduced duration of MRI measurements., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The viologen-skeleton reacts with a hydrazine-terminated cyclotriphosphazene core to provide novel dendritic macromolecular asterisks that efficiently exchange, deliver and stabilize gold nanoparticles for up to eight months.

NiCo bimetallic nanostructures with various morphologies have been synthesized using a broad range of solvents, surfactants and precursors that are available in the metal-organic chemical toolbox. Polygonal particles, nanowires and isotropic nanospheres have been obtained, among others. We describe the chemical pathways to achieve anisotropic growth either by an 'in situ' seed-mediated approach or by simply selecting suitable reaction media and growth modifiers. We describe the role of a variety of synthetic factors that influence the final shape of such an alloy material at the nanoscale. The alloying between cobalt and nickel is evidenced by XRD and HRTEM techniques. Room-temperature ferromagnetic behavior is observed for NiCo nanoparticles and high values for saturation magnetization and coercivity are recorded by SQuID magnetometry. The saturation magnetization value for the NiCo nanostructures is typically set between the corresponding "bulk" ones of cobalt and nickel metals. It is always comparable to the suggested value of the Ni50Co50 bulk alloy. The synthetic protocols derived from our extensive study are quantitative and versatile, allowing high reaction yields. Although macroscopic characterization techniques evidence the presence of a stoichiometric NiCo alloy, we show that in certain cases nanoscale characterization analyses are also needed for a more accurate evaluation of the alloy composition at the atomic level.

The control of the metallic nanocrystal shape is of prime importance for a wide variety of applications. We report a detailed research work on metal-organic chemical routes for the synthesis of a highly symmetrical crystal structure. In particular, this study shows the key parameters ensuring the anisotropic growth of nickel nanostructures (fcc crystal). Numerous reaction conditions are investigated (precursors, solvents, temperature, reducing agents, reaction time, and types and ratios of surfactants, such as alkyl amines, carboxylic acids, and phosphine oxides), and their effects on the size and shape of the final product are reported. The role of the growth modifiers and the structuring of the reaction media on the anisotropic growth are demonstrated. This metal-organic approach generates several novel anisotropic nanostructures in a wide size range depending on the reaction conditions. In this way, nanomaterials with reproducible size, shape, and composition are obtained with good yield. Transmission electron microscopy techniques (TEM and HRTEM) are the principal methods for monitoring the morphology.

The scarcity of low temperature syntheses of anatase nanocrystals prompted us to explore the use of surface-reactive fourth generation phosphorus-dendrimers as molds to control the nucleation and growth of titanium-oxo-species during the sol-gel mineralization process. Unexpectedly, the dendritic medium provides at low temperature, discrete anatase nanocrystals (4.8 to 5.2 nm in size), in marked contrast to the routinely obtained amorphous titanium dioxide phase under standard conditions. Upon thermal treatment, heteroatom migration from the branches to the nanoparticle surface and the ring opening polymerization of the cyclophosphazene core provide stable, interpenetrating mesoporous polyphosphazene-anatase hybrid materials (-P[double bond, length as m-dash]N-)n-TiO2. The steric hindrance of the dendritic skeleton, the passivation of the anatase surface by heteroatoms and the ring opening of the core limit the crystal growth of anatase to 7.4 nm and prevent, up to 800 °C, the commonly observed anatase-to-rutile phase transformation. Performing this mineralization in the presence of similar surface-reactive but non-dendritic skeletons (referred to as branch-mimicking dendrimers) failed to generate crystalline anatase and to efficiently limit the crystal growth, bringing thus clear evidence of the virtues of phosphorus dendrimers in the design of novel nanostructured materials.

Schistosomiasis is among the most neglected tropical diseases, since its mode of spreading tends to limit the contamination to people who are in contact with contaminated waters in endemic countries. Here we report the in vitro and in vivo anti-schistosomal activities of trioxaquines. These hybrid molecules are highly active on the larval forms of the worms and exhibit different modes of action, not only the alkylation of heme. The synergy observed with praziquantel on infected mice is in favor of the development of these trioxaquines as potential anti-schistosomal agents.

Very stable suspensions of small sized (c.a. 1.2 nm) and homogeneously dispersed ruthenium nanoparticles (RuNPs) were obtained by decomposition, under H(2), of (η(4)-1,5-cyclooctadiene)(η(6)-1,3,5-cyclooctatriene)ruthenium(0), [Ru(COD)(COT)], in various imidazolium derived ionic liquids (ILs: [RMIm][NTf(2)] (R = C(n)H(2n+1) where n = 2; 4; 6; 8; 10) and in the presence of amines as ligands (1-octylamine, 1-hexadecylamine). These nanoparticles were compared to others stabilized either in pure ILs or by the same ligands in THF. NMR experiments ((13)C solution and DOSY) demonstrate that the amines are coordinated to the surface of the RuNPs. These RuNPs were investigated for the hydrogenation of aromatics and have shown a high level of recyclability (up to 10 cycles) with neither loss of activity nor significant agglomeration.

The reduction of [Pt(COD)(CH3)2] with CO in the presence of hexadecylamine (HDA) and oleic acid (OlAc) leads to amine carbonylation and formation of an air-stable colloidal solution of N,N'-bis(hexadecyl)urea-stabilized Pt(0) nanoparticles. These air-stable colloidal solutions can be used to form thin films of Pt nanoparticles on a silicon substrate.

15-Membered tri-olefinic azamacrocycles as end-groups of phosphorus-containing dendrimers from generation 1 to 4 are used for obtaining Pt nanoparticles in mild conditions; remarkable and unprecedented branched supramolecular assemblies composed of dendrimers and coalesced Pt nanoparticles are obtained, which become larger for higher dendrimer generations, affording for the first time a very unique organization of organic dendritic structures interweaved with inorganic dendritic structures.

Maghemite (gamma-Fe(2)O(3)) nanoparticles stabilized by long-alkyl-chain amines are synthesized by using an organometallic approach. This method consists of the hydrolysis and oxidation of an organometallic precursor, Fe[N(SiMe(3))(2)](2), in the presence of amine ligands as stabilizing agent in an organic solvent, namely tetrahydrofuran or toluene. Whatever the experimental conditions, particles with a diameter of 2.8 nm are obtained. The use of high-resolution transmission electron microscopy and wide-angle X-ray scattering, together with Mössbauer spectroscopy and SQuId magnetometry, allows a complete characterization of these particles. Herein, we show that their structure is composed of a well-ordered core surrounded by a more disordered shell. The size of the latter varies from 0.65 to 0.50 nm depending on the experimental conditions and is of prime importance for the understanding of the magnetic properties. We demonstrate that the shorter the alkyl chain length of the amine 1) the better the crystallinity of the particle's core and 2) the stronger the interparticle interactions.

The structure of bis[4,5-ethylenedithio-2-(4,5-ethylenedithio-1,3-diselenacyclopent-4-en-2-ylidene)-1,3-diselenacyclopent-4-enium] bis(mu-1,2,5-thiadiazole-3,4-dithiolato-kappa3S4,S5:S4)bis[(1,2,5-thiadiazole-3,4-dithiolato-kappa2S4,S5)iron(III)], (BETS)(2)[Fe(tdas)(2)](2) [BETS is alternatively called bis(ethylenedithio)tetraselenafulvalenium] or (C(10)H(8)S(4)Se(4))(2)[(Fe(C(2)N(2)S(3))(2))(2)], consists of segregated columns of dimers of BETS and columns of dimers of [Fe(tdas)(2)]. Each dimer displays inversion symmetry. Numerous chalcogen-chalcogen contacts are observed within and between the columns, producing a network of interactions responsible for the metal-like behaviour of the compound.