Buchwald–Hartwig Amination of Nitroarenes

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• First published: 22 September 2017Full publication history
• DOI: 10.1002/anie.201706982
• Abstract
  The Buchwald–Hartwig amination of nitroarenes was achieved for the first time by using palladium catalysts bearing dialkyl(biaryl)phosphine ligands. These cross-coupling reactions of nitroarenes with diarylamines, arylamines, and alkylamines afforded the corresponding substituted arylamines. A catalytic cycle involving the oxidative addition of the Ar−NO2 bond to palladium(0) followed by nitrite/amine exchange is proposed based on a stoichiometric reaction.

Pt/Cu single-atom alloys as coke-resistant catalysts for efficient C – H activation

Pt/Cu single-atom alloys as coke-resistant catalysts for efficient C–H activation

M. D. Marcinkowski, M. T. Darby, J. Liu, J. M. Wimble, F. R. Lucci, S. Lee, A. Michaelides, M. Flytzani-Stephanopolous, M. Stamatakis, E. C. H. Sykes

Nature Chem. 2018, ASAP
DOI: 10.1038/nchem.2915

Abstract:

The recent availability of shale gas has led to a renewed interest in C–H bond activation as the first step towards the synthesis of fuels and fine chemicals. Heterogeneous catalysts based on Ni and Pt can perform this chemistry, but deactivate easily due to coke formation. Cu-based catalysts are not practical due to high C–H activation barriers, but their weaker binding to adsorbates offers resilience to coking. Using Pt/Cu single-atom alloys (SAAs), we examine C–H activation in a number of systems including methyl groups, methane and butane using a combination of simulations, surface science and catalysis studies. We find that Pt/Cu SAAs activate C–H bonds more efficiently than Cu, are stable for days under realistic operating conditions, and avoid the problem of coking typically encountered with Pt. Pt/Cu SAAs therefore offer a new approach to coke-resistant C–H activation chemistry, with the added economic benefit that the precious metal is diluted at the atomic limit.

Preparation and Characterization of Bimetallic Pd-Cu Colloids by Thermal Decomposition of Their Acetate Compounds in Organic Solvents

Preparation and Characterization of Bimetallic Pd-Cu Colloids by Thermal Decomposition of Their Acetate Compounds in Organic Solvents

Kunio Esumi, Takafumi Tano, Kanjiro Torigoe, and Kenjiro Meguro
University of Tokyo

Chem. Mater. 1990, 2, 564-567  (http://pubs.acs.org/doi/pdf/10.1021/cm00011a019)

Abstract:

Bimetallic Pd-Cu/Cu2O colloids are prepared by the thermal decomposition of their acetates dissolved in methyl isobutyl ketone and bromobenzene. In methyl isobutyl ketone, the average diameter of Pd-Cu2O colloids decreases from about 130 to 50 nm with an increase of molar fraction of palladium acetate, while in bromobenzene the size of Pd-Cu colloids increases from about 8 to 15 nm. The composition of Pd-Cu or Pd-Cu2O colloids is almost hte same as that of the feed ratio of their acetates. The dispersion stability of these colloids is further addressed by measuring their ζ potentials.