Person: Martín Aranda, Rosa María
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Martín Aranda
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Rosa María
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Publication Developing strategies for the preparation of Co-carbon catalysts involved in the free solvent selective synthesis of aza-heterocycles(Elsevier, 2018-02) Godino Ojer, Marina; Pérez Cadenas, Agustín Francisco; Pérez Mayoral, María Elena; Martín Aranda, Rosa MaríaWe report herein different series of new zero valent Cobalt nanocarbons, as doped and supported aerogels, able to efficiently catalyze the reaction of 2-amino-5-chlorobenzaldehyde and -ketoesters, via Friedländer reaction. The reaction works under solvent-free and mild conditions affording yields over 80% in only 30 min of reaction time. The catalysts could be reused almost during two consecutive cycles without almost any activity loss. A comparative study between supported and doped-carbon aerogels, as catalysts highly efficient in the reaction, has allowed to stablish the relationship between the catalyst structure and the catalytic performance. At this regard, different parameters such as carbonization temperature and surface chemistry on the aerogels under study have been also explored. As a result, although the carbon matrix is involved in the reaction, the Co(0) nanoparticles on the carbon surface are the predominant active catalytic species. Oxygen functionalities on the oxidized samples in the surroundings of Co(0) nanoparticles probably prevent the access of the reagents, notably decreasing their catalytic performance.Publication Tantalum vs Niobium MCF nanocatalysts in the green synthesis of chromene derivatives(Elsevier, 2019-03-15) Smuszkiewicz, Agata; López Sanz, Jesús; Sobczakb, Izabela; Ziolek, María; Martín Aranda, Rosa María; Pérez Mayoral, María ElenaTaMCF silicas modified with alkaline metals can be considered a novel family of highly efficient bifunctional catalysts involved in the synthesis of chromene derivatives, from salicylaldehyde 2 and acetonitrile compounds, under mild conditions, showing enhanced catalytic performance than their NbMCF analogues. The observed reactivity was mainly attributed to the higher basicity of the Me/TaMCF but also the texture of the samples. The Me/TaMCF silicas showed higher Brønsted basicity than the Nb ones as indicated by the stronger interaction between alkali metals and Ta in the UV–vis and the test reaction experiments. On the other hand, the basicity of Me/TaMCF together the reactivity degree and steric hindrance of the starting acetonitriles are key factors influencing the reaction selectivity. In conclusion, the basicity of the samples plays an important role initiating the reaction by activation of nucleophile but also a compromise between alkaline cation size and basicity is required.Publication Eco-friendly catalytic systems based on MgO- Supporting carbon materials for the Friedländer condensation(Wiley, 2014-12) Godino Ojer, Marina; López Peinado, Antonio José; Przepiórski, J.; Pérez Mayoral, María Elena; Soriano, E.; Martín Aranda, Rosa MaríaCarbon-supported MgO materials are excellent and sustainable catalysts for the synthesis of N-containing heterocyclic compounds by the Friedländer condensation under mild, solvent-free conditions. The results reported herein indicate that MgO is the most active catalytic species that accelerates the reaction compared with the catalytic behavior observed for the carbon material Norit RX3. On the basis of DFT calculations, a reaction mechanism that involves dual activation of the reacting structures by the catalyst is proposed. Oxide, outside: MgO supported on carbon is able to catalyze the synthesis of interesting N-containing heterocyclic compounds efficiently under mild conditions. MgO on the carbon surface is responsible for the catalytic behavior. These carbon materials are environmentally friendly catalysts for the Friedländer reaction.