C–C Coupling on Single-Atom-Based Heterogeneous Catalyst

• DOI: 10.1021/jacs.7b09314
• Publication Date: 2017-12-21T01:14:25Z
• Authors: Xiaoyan Zhang; Zaicheng Sun; Bin Wang; Yu Tang; Luan Nguyen; Yuting Li; Franklin Feng Tao
• Keywords: Diphenylacetylene; Iodobenzene; Phenylacetylene; Sonogashira coupling; Homogeneous Catalysis

Compared to homogeneous catalysis, heterogeneous catalysis allows for ready separation of products from the catalyst and thus reuse catalyst. C-C coupling is typically performed on a molecular which mixed with reactants in liquid phase during catalysis. This mixing at level same makes extremely challenging costly. Here we demonstrated that TiO2-based nanoparticle anchoring singly dispersed Pd atoms (Pd1/TiO2) selective highly active more than 10 Sonogashira reactions (R≡CH + R'X → R≡R'; X = Br, I; R' aryl or vinyl). The between iodobenzene phenylacetylene Pd1/TiO2 exhibits turnover rate 51.0 diphenylacetylene molecules per anchored atom minute 60 °C, low apparent activation barrier 28.9 kJ/mol no cost separation. DFT calculations suggest single bonded surface lattice oxygen TiO2 acts as site dissociatively chemisorb generate an intermediate phenyl, then couples phenylacetylenyl bound atom. phenyl adsorbed Pd1 Oad forms product molecule, diphenylacetylene.