Department of Chemistry, University of California at Irvine (UCI), Irvine, California 92677-2025, United States.
Inorg Chem. 2021 Feb 1;60(3):1579-1589. doi: 10.1021/acs.inorgchem.0c02981. Epub 2021 Jan 12.
The ligand-centered hydrogen-atom-transfer (HAT) reactivity was examined for a family of group 10 metal complexes containing a tridentate pincer ligand derived from bis(2-mercapto--tolyl)amine, [SNS]H. Six new metal complexes of palladium and platinum were synthesized with the [SNS] ligand platform in different redox and protonation states to complete the group 10 series previously reported with nickel. The HAT reactivity was examined for this family of nickel, palladium, and platinum complexes to determine the impact of a metal ion on the ligand-centered reactivity. Thermodynamic measurements revealed that N-H bond dissociation free energies increased by approximately 10 kcal mol along the series Ni < Pd < Pt driven by changes to both the redox potential and p of the ligand. Kinetic analyses for all three metal complexes suggest that the barrier to the HAT reactivity is primarily entropic rather than enthalpic for this system.
研究了一组包含源自双（2-巯基--甲苯）胺的三齿钳配体[SNS]H 的第 10 族金属配合物的配体中心氢原子转移 (HAT) 反应性。合成了六种具有不同氧化还原态和质子化态的钯和铂新型金属配合物，具有[SNS]配体平台，以完成先前报道的镍的第 10 族系列。研究了这一系列镍、钯和铂配合物的 HAT 反应性，以确定金属离子对配体中心反应性的影响。热力学测量表明，N-H 键离解自由能沿 Ni < Pd < Pt 系列增加了约 10 kcal/mol，这是由配体的氧化还原电位和 p 的变化驱动的。对所有三种金属配合物的动力学分析表明，对于该体系，HAT 反应性的障碍主要是熵驱动的，而不是焓驱动的。
