N-Site Regulation of Pyridyltriazole in Cp*Ir(N̂N)(H<sub>2</sub>O) Complexes Achieving Catalytic FA Dehydrogenation
作者:Shun Ge、Lishan Gong、Pingping Yi、Xiufang Mo、Chao Liu、Xiao-Yi Yi、Piao He
DOI:10.1021/acs.inorgchem.3c01649
日期:2023.11.13
A series of novel Cp*Ir complexes with nitrogen-rich N̂N bidentate ligands were developed for the catalytic dehydrogenation of formic acid in water under base-free conditions. These complexes were synthesized by using pyridyl 1,2,4-triazole, methylated species, or pyridyl 1,2,3-triazole as a N-site regulation ligand and were fully characterized. Complex 1-H2O bearing 1,2,4-triazole achieved a high
开发了一系列具有富氮N̂N二齿配体的新型Cp*Ir配合物,用于在无碱条件下催化水中甲酸脱氢。这些配合物是通过使用吡啶基 1,2,4-三唑、甲基化物质或吡啶基 1,2,3-三唑作为 N 位调节配体合成的,并进行了充分表征。带有 1,2,4-三唑的复合物1-H 2 O在 4 M FA 水溶液中在 90 °C 下实现了 14192 h –1的高周转频率。通过1 H NMR 和质谱测量成功检测到1-H 2 O的末端和桥接 Ir-H 中间体。进行了动力学同位素效应实验和密度泛函理论(DFT)计算;然后提出了一种涉及β-氢化物消除和H 2形成的合理机制。水辅助H 2释放被证明是反应的速率决定步骤。三唑配体N原子上Mulliken电荷的分布内部揭示了1-H 2 O的邻位N2具有较高的电子密度,有利于有效的质子转移。此外,1,2,4-三唑部分的水辅助短程桥的优势导致1-H 2 O具有更高的催化活性。这项研究证明了富氮配体对