Copper integrative catalytic pairs with mixed-valence Cu2+-Cu3+ Species for selective alkyne conversion
Yuxue Yue, Mingde Yu, Zhangyi Yao, Guangzong Fang, Bolin Wang, Saisai Wang, Chunxiao Jin, Renqin Chang, Tulai Sun, Zhiyan Pan, Yihan Zhu, Feng Ryan Wang, X. G. Li, Jia Zhao
Abstract
Abstract Achieving specific orbital activation of C ≡ C by controlling the precise atomic architecture of supported metals is crucial for the selective transformation of alkynes. However, its physical mechanism remains a subject of debate. Herein, we construct a well-defined O-bridged CuN 3 -O-CuN 3 integrative catalytic pairs (Cu ICPs) based on Kirkendall effect. As a result, Cu ICPs with mixed Cu 2+ -Cu 3+ species demonstrate >99% conversion and >550 h stability in acetylene hydrochlorination (simulated industrial reaction conditions), showcasing unparalleled performance in the liquid-phase hydrochlorination of five alkynes as well. A combined experimental and theoretical analyses reveal selective coupling between the d xz / d yz orbitals of Cu ICPs and the σ orbitals of C ≡ C in C 2 H 2 , leading to the formation of highly reactive di- σ -HC = CH intermediate. Additionally, the presence of the bridged-O species promotes HCl dissociation, altering the addition pathway from the classical Eley-Rideal (E-R) mechanism to a Cl•-trigged Langmuir-Hinshelwood (L-H) mechanism, ultimately reducing the intrinsic energy barrier for addition, and breaking the universal standard electrode potential linear scaling relations.