Department of Chemistry, Southern Methodist University, Dallas, Texas, 75275, United States.
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland, 21218, United States.
Chem Asian J. 2021 Jun 14;16(12):1608-1618. doi: 10.1002/asia.202100286. Epub 2021 May 13.
In this research article, we describe the synthesis and characterization of mononuclear and dinuclear Cu complexes bound by a family of tridentate redox-active ligands with tunable H-bonding donors. The mononuclear Cu-anion complexes were oxidized to the corresponding "high-valent" intermediates by oxidation of the redox-active ligand. These species were capable of oxidizing phenols with weak O-H bonds via H-atom abstraction. Thermodynamic analysis of the H-atom abstractions, which included reduction potential measurements, pK determination and kinetic studies, revealed that modification of the anion coordinated to the Cu and changes in the H-bonding donor did not lead to major differences in the reactivity of the "high-valent" CuY complexes (Y: hydroxide, phenolate and acetate), which indicated that the tridentate ligand scaffold acts as the H and e acceptor.
在这篇研究文章中，我们描述了单核和双核 Cu 配合物的合成和表征，这些配合物通过一系列具有可调氢键供体的三齿氧化还原活性配体结合。单核 Cu-阴离子配合物通过氧化还原活性配体的氧化被氧化为相应的“高价”中间体。这些物种能够通过 H 原子的提取来氧化具有弱 O-H 键的酚。通过还原电势测量、pK 值测定和动力学研究对 H 原子提取的热力学分析表明，Cu 配位的阴离子的修饰以及氢键供体的变化并没有导致“高价”CuY 配合物（Y：氢氧根、酚盐和醋酸盐）的反应性发生重大差异，这表明三齿配体支架充当 H 和 e 受体。
