Issue 9, 2018

Polyhedral Cu2O to Cu pseudomorphic conversion for stereoselective alkyne semihydrogenation

Abstract

Cu2O cubes, octahedra, and rhombic dodecahedra can be pseudomorphically converted into Cu crystals of corresponding shapes through reduction by ammonia borane in ethanol at 50 °C or below within 3 min, demonstrating the feasibility of making challenging polyhedral metal particles from metal oxide crystals. Hydrogen gas is also produced from ammonia borane in the process. The obtained Cu crystals have a slightly nanoporous interior. Addition of diphenylacetylene in the formation of Cu rhombic dodecahedra leads to complete stereoselective production of sterically hindered (Z)-stilbene. Semihydrogenation of other alkynes also gives pure (Z)-alkenes. Cu cubes and octahedra also showed considerable (Z)-stilbene selectivity along with minor formation of (E)-stilbene and bibenzyl as compared to CuCl2 and commercial Cu2O particles. Mechanistic studies reveal that the low binding affinity of alkenes on the rhombic dodecahedra surfaces leads to high product selectivity. These Cu crystals act as a green and low-cost catalyst for the synthesis of high-purity (Z)-alkenes.

Graphical abstract: Polyhedral Cu2O to Cu pseudomorphic conversion for stereoselective alkyne semihydrogenation

Supplementary files

Article information

Article type
Edge Article
Submitted
10 Dec 2017
Accepted
29 Jan 2018
First published
31 Jan 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2018,9, 2517-2524

Polyhedral Cu2O to Cu pseudomorphic conversion for stereoselective alkyne semihydrogenation

S. Rej, M. Madasu, C. Tan, C. Hsia and M. H. Huang, Chem. Sci., 2018, 9, 2517 DOI: 10.1039/C7SC05232D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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