A Platinum molecular complex immobilised on the surface of graphene as active catalyst in alkyne hydrosilylation

Abstract A platinum complex bearing a N‐heterocyclic carbene (NHC) ligand functionalised with a pyrene‐tag is immobilised onto the surface of reduced graphene oxide (rGO). The hybrid material composed of an organometallic complex and a graphene derivative is ready available in a single‐step process under mild reaction conditions. This methodology preserves the inherent properties of the active catalytic centre and the support. The platinum hybrid material is an efficient catalyst in hydrosilylation of alkynes and can be recycled and reused for ten runs without significant loss of activity due to its high stability. Interestingly, the catalytic properties of the platinum complex are enhanced after immobilisation onto graphene. The influence of graphene in hydrosilylation of alkynes is discussed

Dual role of graphene as support of ligand-stabilized palladium nanoparticles and carbocatalyst for (de)hydrogenation of N-heterocycles

The hybrid material composed of palladium nanoparticles (PdNPs) functionalized with N-heterocyclic carbene ligands (NHCs) immobilized onto the surface of reduced graphene oxide (rGO) results in an efficient catalytic material towards hydrogenation and dehydrogenation of N-heterocycles. The rGO plays a dual role by acting as a carbocatalyst in acceptorless dehydrogenation of N-heterocycles and as a support for the palladium nanoparticles facilitating its interaction with molecular hydrogen turning this hybrid material into an effective hydrogenation catalyst. Hot filtration experiments support the heterogeneous nature of the process underlining the strong interaction of palladium nanoparticles with the graphene enabled by π-interactions of the ligand with the support. The mild conditions used in both transformations of this system without requiring any additives facilitates its potential application in hydrogen storage technologies in the form of liquid organic hydrogen carriers (LOHCs). At the same time, the hybrid material is a robust and efficient catalytic platform that can be recovered and reused up to eight runs in both transformations without significant deactivation. The use of a single solid catalysts that is recyclable in hydrogen conversion and reconversion through (de)hydrogenation of N-heterocycles paves the way for the development of efficient hydrogen storage materials

Reduced Graphene Oxides as Carbocatalysts in Acceptorless Dehydrogenation of N-Heterocycles

[EN] The catalytic properties of graphene-derived materials are evaluated in acceptorless dehydrogenation of N-heterocycles. Among them, reduced graphene oxides (rGOs) are active (quantitative yields in 23 h) under mild conditions (130 degrees C) and act as efficient heterogeneous carbocatalysts. rGO exhibits reusability and stability at least during eight consecutive runs. Mechanistic investigations supported by experimental evidence (i.e., organic molecules as model compounds, purposely addition of metal impurities and selective functional group masking experiments) suggest a preferential contribution of ketone carbonyl groups as active sites for this transformation.Supported by MCIN/AEI/10.13039/501100011033/FEDER (Grant Nos. RTI2018-098237-B-C21, RTI2018-098237-BC22, and PID2019-105881RB-I00), Generalitat Valenciana (No. PROMETEU/2020/028), and Universitat Jaume I (No. UJI-B2018-23).Mollar-Cuni, A.; Ventura-Espinosa, D.; Martin, S.; García Gómez, H.; Mata, JA. (2021). Reduced Graphene Oxides as Carbocatalysts in Acceptorless Dehydrogenation of N-Heterocycles. ACS Catalysis. 11(23):1-6. https://doi.org/10.1021/acscatal.1c04649S16112

Stabilization of Nanoparticles Produced by Hydrogenation of Palladium–N-Heterocyclic Carbene Complexes on the Surface of Graphene and Implications in Catalysis

Palladium nanoparticles (NPs) have been obtained by decomposition of well-defined palladium complexes noncovalently anchored onto the surface of reduced graphene oxide. Morphological analysis by microscopy showed the presence of small palladium NPs homogeneously distributed on the support. Characterization by X-ray photoelectron spectroscopy confirmed that palladium NPs contain Pd(2+) and Pd(0) oxidation states and the presence of N-heterocyclic carbene and bromo ligands. The catalytic properties of the NPs with and without the support have been evaluated in the hydrogenation of alkynes. Supported palladium NPs showed increased activity versus the nonsupported ones and could be recycled up to 10 times without the loss of catalytic activity. The composition of the palladium NPs is different for each catalytic cycle indicating a dynamic process and the formation of different catalytic active species. On the contrary, the unsupported palladium NPs showed limited activity caused by decomposition and could not be recycled. The role of the support has been investigated. The results indicate that the support influences the stability of palladium NPs

Semi-hydrogenat to obtain nhc complex reduced hydrogenation of alkynes z-alkenes using a pd anchored onto graphene oxide

Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic: 2016/201

Design of catalytic systems for sustainable processes development: hydrogen storage and biomass transformation

Compendi d'articles, Doctorat internacionalThe present PhD. Thesis is the result of research efforts directed towards the design and development of more sustainable catalytic processes trying to address some of the current challenges that today our society is facing such as the seek for clean energy alternatives, the reduction of environmental pollution and industrial waste (greenhouse gases, sewage), as well as to increase the use of renewable resources. To contribute to this arduous task, the 12 principles of Green Chemistry have been followed as a guide. Special attention has been paid to the use of catalysis, the development of atom economical processes, design for efficient energy relevant to the hydrogen economy and the use of biomass transformation. For this purpose, novel strategies to improve both, heterogeneous and homogeneous catalytic processes have been studied and are now found within this PhD Thesis.Programa de Doctorat en Cièncie

Selective hydrosilylation of Alkynes to obtanin vinyl-silanes using a Pt-NHC complex

Treball Final de Màster Universitari en Química Aplicada i Farmacològica. Codi: SIM138. Curs: 2017/2018The aim of this work is to study the catalytic properties of a platinum molecular complex and the related hybrid material prepared by immobilization of the molecular complex onto reduced graphene oxide by non-covalent interactions. This objective can be divided into the following items: • Synthesis and characterization of an imidazolium salt that would serve as ligand precursor. • Synthesis of a new Pt-NHC complex and full characterization by 1H NMR, APT NMR, COSY, HMBC, HRMS, X-Ray diffraction and TGA • Immobilization and characterization by TEM and ICP-MS of the Pt-NHC complex onto rGO • Study of the catalyst properties of both systems in the hydrosilylation of alkynes. • Study of recyclability of the hybrid material in the hydrosilylation of alkynes. • Study the mechanism of the hydrosilylation of alkynes reactio

Supporting Information for Dual role of graphene as support of ligand-stabilized palladium nanoparticles and carbocatalyst for (de)hydrogenation of N-heterocycles

Appendix A. Supplementary data: Multimedia component 1.Peer reviewe

Introducing Catalysis to Undergraduate Chemistry Students: Testing a Ru–NHC Complex in the Selective Dehydrogenative Coupling of Hydrosilanes and Alcohols

This work describes a complete laboratory experiment that involves the synthesis of a ruthenium complex [Ru(p-cym)(NHC)Cl2] (NHC = N-heterocyclic carbene) and its use as a catalyst for the coupling of hydrosilanes and alcohols. The hydrogen gas produced in the reaction is measured using an inverted buret to trap the gas which allows student to monitor the evolution of the reaction. The complete experience constitutes an opportunity to focus on experimental skills and fundamental concepts in organometallic chemistry and catalysis