51265-33-9Relevant articles and documents
Tailoring graphene-supported Ru nanoparticles by functionalization with pyrene-tagged N-heterocyclic carbenes
Cerezo-Navarrete, Christian,Corma, Avelino,García-Zaragoza, Adrián,Martínez-Prieto, Luis M.,Mata, Jose A.,Mollar-Cuni, Andrés,O?a-Burgos, Pascual
, p. 1257 - 1270 (2022/03/02)
The catalytic properties of graphene-supported ruthenium nanoparticles (Ru@rGO) have been finely tuned by modifying their metal surface with pyrene-tagged N-heterocyclic-carbene ligands (pyr-IMes). The nature and interaction modes of the pyr-IMes ligands on Ru@rGO were established by XPS, which were found as protonated carbenes, coordinated to the ruthenium surface and directly interacting with the graphene support. To evaluate the activity and selectivity of Ru@rGO functionalized with different equivalents of pyr-IMes (Ru@rGO/pyr-IMesn; n = 0, 0.2, 0.5, 0.8 or 1), we used acetophenone hydrogenation as a model reaction. The catalytic activity and selectivity are highly dependent on the NHC surface coverage degree. The higher the amount of surface NHC ligands, the lower the activity of the catalyst, but the higher the selectivity towards 1-phenylethanol (suppressing the hydrodeoxygenation side reaction at high surface coverages). The reactivity of the most interesting catalyst, Ru@rGO/pyr-IMes0.5, was evaluated in the hydrogenation of other molecules of interest, such as nitrobenzene, 5-hydroxymethylfurfural (HMF), quinoline or 1-methylindole, among others. Finally, by TEM analysis after catalysis we observed a clear correlation between the surface ligand coverage and the stability of the catalysts against sintering. It was then possible to control the reactivity and stability of graphene-supported Ru NPs by modifying their surface with pyr-IMes ligands.
The effect of substitution on the utility of piperidines and octahydroindoles for reversible hydrogen storage
Cui, Yi,Kwok, Samantha,Bucholtz, Andrew,Davis, Boyd,Whitney, Ralph A.,Jessop, Philip G.
, p. 1027 - 1037 (2008/12/20)
Substituted piperidines and octahydroindoles are compared in terms of their usability as reversible organic hydrogen storage liquids for hydrogen-powered fuel cells. Theoretical Gaussian calculations indicate which structural features are likely to lower the enthalpy of dehydrogenation. Experimental results show that attaching electron donating or conjugated substituents to the piperidine ring greatly increases the rate of catalytic dehydrogenation, with the greatest rates being observed with 4-aminopiperidine and piperidine-4-carboxamide. Undesired side reactions were observed with some compounds such as alkyl transfer reactions during the dehydrogenation of 4-dimethylaminopiperidine, C-O and C-N cleavage reactions during hydrogenation and/or subsequent dehydrogenation of 4-alkoxy and 4-amino indoles, and disproportionation during the hydrogenation of 4-aminopyridine. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
SYNTHESIS OF TRI- AND TETRAMETHYLENEPYRROLE DERIVATIVES FROM 2-(1-ETHOXY-2-BROMOETHYL)CYCLOALKANONES
Azzuz, A.,Sorokin, V. L.,Kulinkovich, O. G.
, p. 31 - 33 (2007/10/02)
Tri- and tetramethylenepyrrole derivatives were synthesized by treatment of the corresponding 2-(1-ethoxy-2-bromoethyl)cycloalkanones with an aqueous solution of sodium hydroxide and a methanol solution of a primary amine.The transformation proceeds th
