Oxidation or Reduction State of Au Stabilized by an MOF: Active Site Identification for the Three‐Component Coupling Reaction. Issue 12 (4th October 2018)

• Record Type: Journal Article
• Authors: Yang, Qihao; Jiang, Hai‐Long
• Is Part Of: Small methods. Volume 2:Issue 12(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-10-04
• Subjects: A3 coupling -- active site identification -- Au catalysis -- metal–organic frameworks; Nanotechnology -- Methodology -- Periodicals; Nanotechnology -- Periodicals; Periodicals; 620.5028
• DOI: 10.1002/smtd.201800216
• Languages: English
• ISSNs: 2366-9608

Abstract

Abstract: As one of the most efficient catalysts for the three‐component coupling reaction of aldehyde, amine, and alkyne (A 3 coupling), Au has attracted extensive attention, but there is a debating issue on whether Au δ + (δ > 0, representing the oxidation state of Au species) or Au 0 is the better active site. According to previous reports, both Au δ + and Au 0 can catalyze the A 3 coupling reaction. Therefore, the establishment of a suitable comparison model to identify the better active site is highly desired. In this work, an ideal model to identify the efficient active sites for the A 3 coupling reaction based on a metal–organic framework (MOF) platform is rationally fabricated. The Au δ + in oxidation state can be well bound to the MOF, MIL‐101‐NH2, via postsynthetic modification, and the Au 0 catalyst with retained MOF skeleton can be formed via a subsequent one‐step reduction, which provide ideal comparison models with the only difference in the Au oxidation state. Strikingly, the two catalysts exhibit significant activity difference in the A 3 coupling reaction. The activity of Au δ + catalyst is 11‐fold higher than that of Au 0, which reveals that Au δ + serves as a much more effective active site in the A 3 coupling reaction. Abstract : The oxidation and reduction states of Au species have been rationally stabilized based on a metal–organic framework (MOF) platform, offering an ideal model to identify the efficient active site. Strikingly, Au δ + exhibits an 11‐fold higher activity than that of Au 0 toward the A 3 coupling reaction, suggesting that the former is much more active.