0000000001306827
AUTHOR
Alejandra Rendón-patiño
A reliable procedure for the preparation of graphene-boron nitride superlattices as large area (cm x cm) films on arbitrary substrates or powders (gram scale) and unexpected electrocatalytic properties
[EN] Herein, a reliable procedure for the preparation of graphene-boron nitride superlattices, either as films or powders, consisting of the pyrolysis at 900 degrees C of polystyrene embedded pre-formed boron nitride single sheets is reported. The procedure can serve to prepare large area films (cm x cm) of this superlattice on quartz, copper foil and ceramics. Selected area electron diffraction patterns at every location on the films show the occurrence of the graphene-boron nitride superlattice all over the film. The procedure can also be applied to the preparation of powdered samples on a gram scale. Comparison with other materials indicates that the superlattice appears spontaneously as…
Organocatalytic Enantioselective Functionalization of Hydroxyquinolines through an Aza-Friedel-Crafts Alkylation with Isatin-derived Ketimines
[EN] A highly enantioselective addition of hydroxyquinolines to isatin-derived ketimines has been realized using a quinine-derived thiourea organocatalyst. The reaction affords chiral 3-amino-2-oxindoles bearing a quinoline moiety with a quaternary stereocenter in high yields (up to 98%) and excellent enantioselectivities (up to 99%). Moreover, we can extend this methodology for the enantioselective functionalization of 5-hydroxyisoquinoline. This methodology represents, to the best of our knowledge, the first enantioselective addition of hydroxyquinolines to imines.
Organocatalytic Enantioselective Friedel–Crafts Aminoalkylation of Indoles in the Carbocyclic Ring
The first general catalytic method for the, so far elusive, enantioselective Friedel−Crafts functionalization of indoles in the carbocyclic ring is presented. This transformation contrasts with the usual tendency of these heterocycles to react at the azole ring. For this purpose, the four regioisomeric hydroxy carbocyclic-substituted indoles were reacted with several isatinderived ketimines, using a Cinchona alkaloid-based squaramide, in a low 0.5−5 mol % catalyst loading, as a bifunctional catalyst. This methodology allows the functionalization of indoles in every position of the carbocyclic ring in a regio- and enantioselective fashion, by switching only the position of the hydroxy group …
Polystyrene as Graphene Film and 3D Graphene Sponge Precursor
[EN] Polystyrene as a thin film on arbitrary substrates or pellets form defective graphene/graphitic films or powders that can be dispersed in water and organic solvents. The materials were characterized by visible absorption, Raman and X-ray photoelectron spectroscopy, electron and atomic force microscopy, and electrochemistry. Raman spectra of these materials showed the presence of the expected 2D, G, and D peaks at 2750, 1590, and 1350 cm(-1), respectively. The relative intensity of the G versus the D peak was taken as a quantitative indicator of the density of defects in the G layer.
Superior Electrocatalytic Activity of MoS2-Graphene as Superlattice
[EN] Evidence by selected area diffraction patterns shows the successful preparation of large area (cm x cm) MoS2/graphene heterojunctions in coincidence of the MoS2 and graphene hexagons (superlattice). The electrodes of MoS2/graphene in superlattice configuration show improved catalytic activity for H-2 and O-2 evolution with smaller overpotential of +0.34 V for the overall water splitting when compared with analogous MoS2/graphene heterojunction with random stacking.
CCDC 1557026: Experimental Crystal Structure Determination
Related Article: Carlos Vila, Alejandra Rendón-Patiño, Marc Montesinos-Magraner, Gonzalo Blay, M. Carmen Muñoz, José R. Pedro|2018|Adv.Synth.Catal.|360|859|doi:10.1002/adsc.201701217
CCDC 1439710: Experimental Crystal Structure Determination
Related Article: Marc Montesinos-Magraner, Carlos Vila, Alejandra Rendón-Patiño, Gonzalo Blay, Isabel Fernández, M. Carmen Muñoz, and José R. Pedro|2016|ACS Catalysis|6|2689|doi:10.1021/acscatal.6b00260
CCDC 1439713: Experimental Crystal Structure Determination
Related Article: Marc Montesinos-Magraner, Carlos Vila, Alejandra Rendón-Patiño, Gonzalo Blay, Isabel Fernández, M. Carmen Muñoz, and José R. Pedro|2016|ACS Catalysis|6|2689|doi:10.1021/acscatal.6b00260
CCDC 1439709: Experimental Crystal Structure Determination
Related Article: Marc Montesinos-Magraner, Carlos Vila, Alejandra Rendón-Patiño, Gonzalo Blay, Isabel Fernández, M. Carmen Muñoz, and José R. Pedro|2016|ACS Catalysis|6|2689|doi:10.1021/acscatal.6b00260