Periodic Reporting for period 1 - PGOLDCAT (Polynuclear Gold Cluster Catalysis)
Berichtszeitraum: 2017-03-01 bis 2019-02-28
With a greater awareness of the size and geometric effects in catalytic behaviours, the atomically precise nanogold clusters such as Au25 naloclusters have been growing into a promising class of model heterogeneous catalysts. An enhancement of catalytic activities of gold nanoparticles by decreasing the size has been reported. Several experimental reports have shown that small gold clusters Aun (n = 3–10) can efficiently catalyse different reactions, such as the hydration of alkynes, the bromination of arenes. Well–defined trinuclear gold species Au02AuI can catalyse the carbonylation of amines. Also, the selective activation of the C–H bond of methane by small gold clusters has been theoretically proven. However, the polynuclear cationic AuI entities still remain less explored in gold catalysis. To date, only a few of catalytically active AuIn clusters (n ≥ 3) have been reported. The trinuclear oxonium gold cluster [(Ph3PAu)3O](BF4) catalysed the cycloisomerization of 1,5-allenyenes, as reported by the group of Toste. Tetranuclear and pentanuclear gold(I)–silver(I) clusters reported by our group have been proven to be active in the carbonylation of amines, and also a hexagold(I) cluster was found to catalyse the cycloisomerization of enynes.
Herein, instead of pursuing the novel monogold complex from the view of ligand, based on the potential application of gold clusters in catalysis, we were trying to take advantage of the unique coordination mode of a hexanuclear gold clusters in the possible activation of alkynes in enyne chemistry. Therefore, our efforts were focused on developing novel gold(I) and gold(I)–silver(I) clusters with new designed TMS-phosphine ligands via AuI/Si transmetallaiton, studying their catalytic reactivity in gold-catalysed systems and applying these clusters in the exploration for further enantioselective gold catalysis.
We have presented our results of this research in our group seminars and also three renowned and scientific conferences:
1) XVI Biennial Meeting - Spanish Royal Society of Chemistry (RSEQ), June 25-29, 2017, Sitges, Spain. In this XVI Biennial conference, we have presented our research titled as ¨Silver Doping of Hexanuclear Gold(I) Clusters Stabilized by Hemilabile Phosphine¨ in the poster section.
2) GOLD 2018, July 15-18, 2018, Paris, France. In this GOLD 2018 conference, we have presented our work titled as ¨Anionic-Arylphosphines-Stabilized Small Gold and Gold-Silver Clusters: From Mono- to Bi-metallic Catalysts¨ in the oral presentation section.
3) ICIQ-INTECAT School, December 11-13, 2018, Tarragona, Spain. In this ICIQ-INTECAT School, we have presented our work titled as ¨ From Mono- to Bi-metallic Catalysts: Anionic-Arylphosphines-Stabilized Small Gold and Gold-Silver Clusters¨ in the oral presentation section and also poster section.
Our results on “Synthesis of Catalytically Active Anionic–aryl–phosphine–protected Hexanuclear Gold/Gold–Silver Clusters via AuI/Si Transmetallation” have attracted several specialists’ attention and recognition during those conferences, and the manuscript on this topic is under preparation.