Inorganic Chemistry in Latin America

The European Journal of Inorganic Chemistry takes pride in showcasing the high-quality research produced by some of the currently most active scientists in Latin America. With this initiative, we seek to highlight the breadth and depth of the science developed in the region, and to enhance its visibility in the wider chemistry community.Fil: Castillo, Ivan. Universidad Nacional Autónoma de México; MéxicoFil: Fadini, Luca. No especifíca;Fil: Doctorovich, Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Rossi, Liane M.. Universidade de Sao Paulo; BrasilFil: González Gallardo, Sandra. No especifíca

Synthesis of supported metal nanoparticle catalysts using ligand assisted methods

The synthesis and characterization methods of metal nanoparticles (NPs) have advanced greatly in the last few decades, allowing an increasing understanding of structure-property-performance relationships. However, the role played by the ligands used as stabilizers for metal NPs synthesis or for NPs immobilization on solid supports has been underestimated. Here, we highlight some recent progress in the preparation of supported metal NPs with the assistance of ligands in solution or grafted on solid supports, a modified deposition-reduction method, with special attention to the effects on NPs size, metal-support interactions and, more importantly, catalytic activities. After presenting the general strategies in metal NP synthesis assisted by ligands grafted on solid supports, we highlight some recent progress in the deposition of pre-formed colloidal NPs on functionalized solids. Another important aspect that will be reviewed is related to the separation and recovery of NPs. Finally, we will outline our personal understanding and perspectives on the use of supported metal NPs prepared through ligand-assisted methods.FAPESPCAPESCNPqINCT-Catalis

Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

The aim of this Account is to provide an overview of our current research activities on the design and modification of superparamagnetic nanomaterials for application in the field of magnetic separation and catalysis. First, an introduction of magnetism and magnetic separation is done. Then, the synthetic strategies that have been developed for generating superparamagnetic nanoparticles spherically coated by silica and other oxides, with a focus on well characterized systems prepared by methods that generate samples of high quality and easy to scale-up, are discussed. A set of magnetically recoverable catalysts prepared in our research group by the unique combination of superparamagnetic supports and metal nanoparticles is highlighted. This Account is concluded with personal remarks and perspectives on this research field

Comparing thermal-cracking and catalytic hydrocracking in the presence of Rh and Ru catalysts to produce liquid hydrocarbons from vegetable oils

Neste trabalho descrevemos a obtenção de hidrocarbonetos líquidos por meio do hidrocraqueamento catalítico de óleo de soja, dendê e mamona, na presença e ausência de catalisadores nanoparticulados de rutênio e ródio. A reação realizada a 200 ºC leva somente à hidrogenação de ligações duplas C=C. No entanto, a 400 ºC, foi observada a decomposição dos triacilglicerídeos, levando a hidrocarbonetos e compostos oxigenados. O hidrocraqueamento catalítico de óleos vegetais na presença de Rh e Ru levou a um aumento da quantidade de produtos desoxigenados e à formação de hidrocarbonetos lineares de cadeia longa, que são adequados para utilização como combustível para motores diesel, quando comparado com o da reação de pirólise na ausência de catalisadores. O catalisador de Ru é mais eficaz do que o catalisador de Rh, especialmente no caso do óleo de mamona, provavelmente devido à sua maior oxofilicidade quando comparado com Rh.We describe herein the production of liquid hydrocarbons through the catalytic hydrocracking of soybean, palm tree and castor oils, in the presence and absence of ruthenium and rhodium nanoparticle catalysts. The reaction at 200 ºC leads to the hydrogenation of C=C double bonds only. However, at 400 ºC, the decomposition of the triacylglycerides was observed, leading to hydrocarbons and oxygenated compounds. The catalyzed hydrocracking of vegetable oils in the presence of Rh and Ru strongly increased the amount of deoxygenated products and the formation of long-chain linear hydrocarbons, which are suitable for use as diesel fuel, when compared with pyrolysis reaction in the absence of the catalysts. The Ru catalyst is more effective than Rh, especially in the case of castor oil, probably due to its higher oxophilicity when compared to Rh

Ruthenium nanoparticles prepared from ruthenium dioxide precursor: Highly active catalyst for hydrogenation of arenes under mild conditions

The hydrogenation of benzene and benzene derivatives was studied using Ru(0) nanoparticles prepared by a very simple method based on the in situ reduction of the commercially available precursor ruthenium dioxide under mild conditions (75 degrees C and hydrogen pressure 4atm) in imidazolium ionic liquids. Total turnovers (TTO) of 2700 mol/mol Ru were obtained for the conversion of benzene to cyclohexane under solventless conditions and TTO of 1200 mol/mol Ru were observed under ionic liquid biphasic conditions. When corrected for exposed ruthenium atoms, TTO values of 7940 (solventless) and 3530 (biphasic) were calculated for benzene hydrogenation. These reaction rates are higher than those observed for Ru nanoparticles prepared from decomposition of an organometallic precursor in similar conditions. The presence of the partially hydrogenated product cyclohexene was also detected at low conversion rates. (C) 2008 Elsevier B.V. All rights reserved.CENPESCENPESFinanciadora de Estudos e Projetos (FINEP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CTPETRO-CNPqFAPERGSFundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS

Gold−Ligand-Catalyzed Selective Hydrogenation of Alkynes into cis- Alkenes via H2 Heterolytic Activation by Frustrated Lewis Pairs

The selective hydrogenation of alkynes to alkenes is an important synthetic process in the chemical industry. It is commonly accomplished using palladium catalysts that contain surface modifiers, such as lead and silver. Here we report that the adsorption of nitrogen-containing bases on gold nanoparticles results in a frustrated Lewis pair interface that activates H2 heterolytically, allowing an unexpectedly high hydrogenation activity. The so-formed tight-ion pair can be selectively transferred to an alkyne, leading to a cis isomer; this behavior is controlled by electrostatic interactions. Activity correlates with H2 dissociation energy, which depends on the basicity of the ligand and its reorganization on activation of hydrogen. High surface occupation and strong Au atom−ligand interactions might affect the accessibility and stability of the active site, making the activity prediction a multiparameter function. The promotional effect found for nitrogen-containing bases with two heteroatoms was mechanistically described as a strategy to boost gold activity

Ligand-Assisted Preparation of Palladium Supported Nanoparticles: a Step toward Size Control

Supported nanoparticles (SNPs) with narrow size distribution were prepared by H(2) reduction of Pd(2+) previously bound, to ligand-modified silica surfaces. Interestingly, the size of the Pd SNPs was tuned by the ligand grafted on the support surface. Amino- and ethylenediamino-functionalized supports formed Pd(0) SNPs of ca. 6 and 1 nm, respectively. The catalytic properties of both Pd(0) SNPs were investigated.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqInstituto Nacional de Ciencia a Tecnologia de Catalise em Sistemas Moleculares a Nanoestruturados (INCT-CMN)Instituto Nacional de Ciencia a Tecnologia de Catalise em Sistemas Moleculares a Nanoestruturados (INCT-CMN)LME-LNLSLME/LNLS[JEM-3010]Campinas[JEM-2100]Campina

Selective oxidation of glucose to glucuronic acid by cesium-promoted gold nanoparticle catalyst

International audienc