Calixarene-functionalized MoS2 nanoparticles as catalysts for HDS reactions

• Applicant: Dr. Christian Schöttle
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation ; Solid State and Surface Chemistry, Material Synthesis ; Synthesis and Properties of Functional Materials
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 325483629

• Final Report Year: 2020

Final Report Abstract

Metalloenzymes have the ability to stabilize metal clusters in accessible and coordinatively unsaturated states, leading to a high activity and selectivity at the active site of the enzyme. An evolving area of synthetic molecule and catalyst design is to mimic the structural features of enzymes to create ever more active and selective catalysts. Using iridium clusters as model systems the Katz group has developed a bioinspired general construct for stabilizing cluster catalysts using bulky calixarene ligands. Due to the very bulky calixarene ligands, the clusters are well protected against aggregation and agglomeration, even under harsh catalytic or electrochemical conditions. But the cluster is still accessible for small molecules (such as H2, CO, ethylene) as the bulky ligands cannot form a closed shell around the cluster. This principle was applied in two different projects: (i) [Ir(CO)2PPhL]2: Bulky Calixarene Ligands Stabilize Supported Iridium Pair-Site Catalysts: Using calixarene-phosphine ligands a new diiridium carbonyl cluster with a unique (crystal) structure has been synthesized. Supported on silica the molecular cluster is suitable for heterogeneous catalysis. The new diiridium catalyst is highly active in hydrogenation catalysis and moreover stable on a molecular level. After over 90 h time on stream there is no significant decrease in catalytic activity observable and the dimeric structure is preserved during harsh catalytic conditions as shown by atomic-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging and extended X-ray absorption fine structure (EXAFS) spectroscopy. Using extended, in-situ spectroscopy the activation and catalysis mechanism was investigated. (ii) Nanoporous gold assemblies of calixarene phosphine-capped colloids:.High surface area nanoporous gold assemblies have been synthesized under electrochemical reducing conditions using calixarene-phosphine gold clusters as building blocks. Depending on the ligand the pore size was tuned. Subsequent UV/ozone treatment allowed the removal of the organic ligands in these materials under retention of their morphology. First experiments in nitrobenzene sensing showed promising results for application.

Publications

• Chem. Commun. 2017, 53, 10870–10873
  C. Schöttle, E. L. Clark, A. Harker, A. Solovyov, A. T. Bell, A. Katz
  
• React. Chem. Eng. 2017, 2, 852–861
  M. Aigner, N. A. Grosso-Giordano, C. Schöttle, A. Okrut, S. Zones, A. Katz
  
• J. Am. Chem. Soc. 2018, 140, 4956–4960
  N. A. Grosso-Giordano, C. Schroeder, A. Okrut, A. Solovyov, C. Schöttle, W. Chassé, N. Marinković, H. Koller, S. I. Zones, A. Katz
  
• Trans. 2018, 47, 15082–15090
  A. Okrut, M. Aigner, C. Schöttle, N. A. Grosso-Giordano, S. J. Hwang, X. Ouyang, S. Zones, A. Katz, Dalt
  
• ACS Appl. Mater. Interfaces 2019, 11, 15189–15194
  C. Schöttle, Y. Xie, Y. Li, C. Carraro, X. Zhang, A. Katz, R. Maboudian
  
• ACS Appl. Mater. Interfaces 2019, 11, 44851–44864
  M. K. Mishra, C. Schöttle, A. Van Dyk, K. Beshah, J. C. Bohling, J. A. Roper, C. J. Radke, A. Katz
  
• Inorg. Chem. 2019, 58, 14338–14348
  A. P. Palermo, C. Schöttle, S. Zhang, N. A. Grosso-Giordano, A. Okrut, D. A. Dixon, H. Frei, B. C. Gates, A. Katz
  
• J. Am. Chem. Soc. 2019, 141, 4010-4015
  C. Schöttle, E. Guan, A. Okrut, N. A. Grosso-Giordano, A. Palermo, A. Solovyov, B. C. Gates, A. Katz
  
• Micropor. Mesopor. Mat. 2019, 283, 55–63
  A. Okrut, N. A. Grosso-Giordano, C. Schöttle, S. Zones, A. Katz