Stability and C-H Bond Activation Reactions of Palladium(I) and Platinum(I) Metalloradicals: Carbon-to-Metal H-Atom Transfer and an Organometallic Radical Rebound Mechanism.
Stability and C-H Bond Activation Reactions of Palladium(I) and Platinum(I) Metalloradicals: Carbon-to-Metal H-Atom Transfer and an Organometallic Radical Rebound Mechanism.
复制标题
DOI：
10.1021/jacs.3c04167
复制
发表时间：
2023-06-28
影响因子：
15
通讯作者：
Chaplin, Adrian B.
中科院分区：
文献类型：
--
作者：
Kramer, Tobias;Gyton, Matthew R.;Bustos, Itxaso;Sinclair, Matthew J. G.;Tan, Sze-yin;Wedge, Christopher J.;Macgregor, Stuart A.;Chaplin, Adrian B.
钯（0）和铂（0）双（膦）配合物的单电子氧化能够分离出一系列同系的线性d⁹金属自由基，其形式为[M(PR₃)₂]⁺（M = Pd，Pt；R = tBu，Ad），当与弱配位的[BArF₄]⁻（ArF = 3,5-(CF₃)₂C₆H₃）抗衡离子结合时，它们在1,2 - 二氟苯（DFB）溶液中于室温下稳定存在超过1天。这些金属自由基在四氢呋喃（THF）中的稳定性降低，稳定性顺序为钯（I）>铂（I）以及PAd₃ > PtBu₃，特别是[Pt(PtBu₃)₂]⁺的情况，它在室温溶解时会转化为铂（II）配合物[Pt(PtBu₂CMe₂CH₂)(PtBu₃)]⁺和[Pt(PtBu₃)₂H]⁺的1:1混合物。[Pt(PtBu₃)₂]⁺的环金属化也可通过与2,4,6 - 三叔丁基苯氧基自由基在DFB中反应来诱导，并且通过计算分析证实了一种常见的自由基回弹机制，该机制涉及碳 - 金属H原子转移以及中间体铂（III）氢化物配合物[Pt(PtBu₂CMe₂CH₂)H(PtBu₃)]⁺的形成。自由基C - H键的氧化加成与所得的Mⁱⁱ - H键解离能相关（M = Pt > Pd），并且金属自由基与9,10 - 二氢蒽在室温下于DFB中的反应为铂的情况下所提出的C - H键活化过程提供了实验证据，尽管[Pt(PtBu₃)₂]⁺（t₁/₂ = 1.2小时）转化为铂（II）氢化物衍生物的速度比[Pt(PAd₃)₂]⁺（t₁/₂ ∼ 40天）快得多。
One-electron oxidation of palladium(0) and platinum(0) bis(phosphine) complexes enables isolation of a homologous series of linear d9 metalloradicals of the form [M(PR3)2]+ (M = Pd, Pt; R = tBu, Ad), which are stable in 1,2-difluorobenzene (DFB) solution for >1 day at room temperature when partnered with the weakly coordinating [BArF4]− (ArF = 3,5-(CF3)2C6H3) counterion. The metalloradicals exhibit reduced stability in THF, decreasing in the order palladium(I) > platinum(I) and PAd3 > PtBu3, especially in the case of [Pt(PtBu3)2]+, which is converted into a 1:1 mixture of the platinum(II) complexes [Pt(PtBu2CMe2CH2)(PtBu3)]+ and [Pt(PtBu3)2H]+ upon dissolution at room temperature. Cyclometalation of [Pt(PtBu3)2]+ can also be induced by reaction with the 2,4,6-tri-tert-butylphenoxyl radical in DFB, and a common radical rebound mechanism involving carbon-to-metal H-atom transfer and formation of an intermediate platinum(III) hydride complex, [Pt(PtBu2CMe2CH2)H(PtBu3)]+, has been substantiated by computational analysis. Radical C–H bond oxidative addition is correlated with the resulting MII–H bond dissociation energy (M = Pt > Pd), and reactions of the metalloradicals with 9,10-dihydroanthracene in DFB at room temperature provide experimental evidence for the proposed C–H bond activation manifold in the case of platinum, although conversion into platinum(II) hydride derivatives is considerably faster for [Pt(PtBu3)2]+ (t1/2 = 1.2 h) than [Pt(PAd3)2]+ (t1/2 ∼ 40 days).
登录
查看更多内容
影响因子：
15
作者：
Butts, MD;Scott, BL;Kubas, GJ
通讯作者：
Kubas, GJ
影响因子：
15
作者：
Diccianni, Justin B.;Katigbak, Joseph;Diao, Tianning
通讯作者：
Diao, Tianning
影响因子：
1.5
作者：
Cui, WH;Wayland, BB
通讯作者：
Wayland, BB
影响因子：
3.9
作者：
Espinoza, Eli M.;Clark, John A.;Vullev, Valentine I.
通讯作者：
Vullev, Valentine I.
影响因子：
15
作者：
Barrière, F;Geiger, WE
通讯作者：
Geiger, WE