Development of a Recyclable and Low‐Leaching Palladium Catalyst Supported on Sulfur‐Modified Gallium Arsenide (001) for Use in Suzuki–Miyaura Coupling

Abstract

A newly developed, environmentally benign palladium catalyst supported on gallium arsenide, {Pd}‐S‐GaAs(001), has both the lowest recorded leaching and high recyclability for Suzuki–Miyaura coupling. Measurements of the catalyst surface by synchrotron radiation X‐ray photoelectron spectroscopy show a relationship between the surface and the activity of the catalyst. Since {Pd}‐S‐GaAs(001) makes efficient use of the rare metal Pd, it is a useful palladium catalyst from an atom‐ economical perspective. Two heterogeneity tests clarify that the presence of immobilized palladium on SGaAs is important for higher catalytic activity.

Hard x-ray photoemission spectroscopic investigation of palladium catalysts immobilized on a GaAs(001) surface

“…This process is almost identical to that described in previous reports. 3,5 The catalyst thus obtained is hereinafter referred to as PSGA ͑Pd-immobilized S-terminated GaAs͒. Among several pieces of PSGA, one of them was kept fresh ͑fresh-PSGA͒, and the rest were subjected to the Heck reaction of iodobenzene and methyl acrylate for up to ten times.…”

“…[1][2][3][4][5] The immobilized catalyst is confirmed to be active enough in the Heck reaction, a well-known palladium-catalyzed reaction for promoting carbon-carbon bond formation between an alkene and an aryl halide ͑see recent review books 6,7 ͒, for over ten times while maintaining high chemical yields. The leaching of Pd after the catalytic reaction can be suppressed to below 1 ppm if the catalyst is prepared with suitable treatments.…”

“…The leaching of Pd after the catalytic reaction can be suppressed to below 1 ppm if the catalyst is prepared with suitable treatments. 4,5 Although it has been found that the developed catalyst has major potentiality for practical use, many unanswered questions remain. The most essential one is the chemical form of palladium species because it is key to understanding the high catalytic activity.…”

Sulfur-mediated palladium catalyst immobilized on a GaAs surface

“…[1][2][3][4][5] The heterogeneous catalyst thus obtained is confirmed to be sufficiently active in the Heck reaction, a palladium-catalyzed reaction that promotes carbon-carbon bond formation between alkenes and aryl halides (see recent review books 6,7 ), over 10 times while maintaining high chemical yields. The leaching of Pd after the catalytic reaction can be suppressed to below 1 ppm if the catalyst is prepared with suitable treatments.…”

“…The leaching of Pd after the catalytic reaction can be suppressed to below 1 ppm if the catalyst is prepared with suitable treatments. 4,5 One of the astonishing features of this catalyst is the presence of S, generally regarded as a poison of various catalytic reactions, including Pd-catalyzed ones. In our catalyst, however, immobilization without S-termination results in a catalyst with lower activity and less efficient recyclability.…”