📍 ICIQ Auditorium Prof. Dr. Kilian Muñiz

⏰  15.30 h

Single-Atom Catalysis for Sustainable Organic Transformations

 Pursuing efficient and environmentally responsible chemical processes has been a constant driver of innovation for synthetic chemists. Single-atom heterogeneous catalysts (SACs), with their well-defined active sites, hold significant promise in this endeavor. However, the spatial constraints and electronic configurations imposed by isolated single atoms anchored on solid supports limit their applicability for catalyzing complex molecular transformations. Building on recently reported approaches to preparing SACs with high metal densities through simple impregnation and controlled thermal annealing, we have developed methods to create SACs, such as palladium and copper, supported on various hosts. These catalysts have shown significant potential in organic synthesis. 

Characterization requires advanced techniques, including scanning transmission electron microscopy, in-situ X-ray absorption spectroscopy, and electron paramagnetic resonance spectroscopy, to confirm the precise coordination and spatial arrangement of the single atoms. Catalytic evaluations in batch and continuous flow systems demonstrate outstanding selectivity and stability in diverse organic transformations, including C–C and C-X cross-couplings. The intrinsic advantages of SACs, including palladium and copper variants, enable the assembly of heterocycles with multiple functional groups and sterically congested scaffolds. Density functional theory simulations support experimental observations, indicating that the remarkable efficiency of SACs lies in their adaptive coordination environments, which facilitate dynamic bonding pathways. 

Moreover, the standardization of SACs through automated synthesis and characterization protocols is essential to overcome existing challenges. By adopting these protocols, we can ensure consistent and reproducible catalyst performance. Lifecycle analysis of catalytic processes involving SACs reveals substantial potential for reducing the environmental footprint compared to conventional homogeneous synthesis, highlighting the benefits of using heterogeneous catalysts in sustainable chemistry. 

Representative references 

1. X. X. Li, S. Mitchell, Y. Fang, J. Li, J. Pérez-Ramírez, J. Lu, Nat. Rev. Chem. 2023, 7, 754. 

2. Z. Chen, E. Vorobyeva, S. Mitchell, E. Fako, M.A. Ortuño, N. López, S.M. Collins, P.A. Midgley, S. Richard, G. Vilé, J. Pérez-Ramírez, Nat. Nanotechnol. 2018, 13, 702 

3. Hai, S. Xi, S. Mitchell, K. Harrath, H. Xu, D. Faust Akl, D. Kong, J. Li, Z. Li, T. Sun, H. Yang, Y. Cui, C. Su, X. Zhao, J. Li, J. Pérez-Ramírez, J. Lu, Nat. Nanotechnol. 2022, 17, 174. 

4. X. Hai, Y. Zheng, Q. Yu, N. Guo, S. Xi, X. Zhao, S. Mitchell, X. Luo, V. Tulus, M. Wang, X. Sheng, L. Ren, X. Long, J. Li, P. He, H. Lin, Y. Cui, X. Peng, J. Shi, J. Wu, C. Zhang, R. Zou, G. Guillén-Gosálbez, J. Pérez-Ramírez, M.J. Koh, Y. Zhu, J. Li, J. Lu, Nature 2023, 622, 754.