Unknown

Dataset Information

0

Mechanisms for Hydrogen-Atom Abstraction by Mononuclear Copper(III) Cores: Hydrogen-Atom Transfer or Concerted Proton-Coupled Electron Transfer?


ABSTRACT: In a possibly biomimetic fashion, formally copper(III)-oxygen complexes LCu(III)-OH (1) and LCu(III)-OOCm (2) (L2- = N,N'-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide, Cm = ?,?-dimethylbenzyl) have been shown to activate X-H bonds (X = C, O). Herein, we demonstrate similar X-H bond activation by a formally Cu(III) complex supported by the same dicarboxamido ligand, LCu(III)-O2CAr1 (3, Ar1 = meta-chlorophenyl), and we compare its reactivity to that of 1 and 2. Kinetic measurements revealed a second order reaction with distinct differences in the rates: 1 reacts the fastest in the presence of O-H or C-H based substrates, followed by 3, which is followed by (unreactive) 2. The difference in reactivity is attributed to both a varying oxidizing ability of the studied complexes and to a variation in X-H bond functionalization mechanisms, which in these cases are characterized as either a hydrogen-atom transfer (HAT) or a concerted proton-coupled electron transfer (cPCET). Select theoretical tools have been employed to distinguish these two cases, both of which generally focus on whether the electron (e-) and proton (H+) travel "together" as a true H atom, (HAT), or whether the H+ and e- are transferred in concert, but travel between different donor/acceptor centers (cPCET). In this work, we reveal that both mechanisms are active for X-H bond activation by 1-3, with interesting variations as a function of substrate and copper functionality.

SUBMITTER: Mandal M 

PROVIDER: S-EPMC7197025 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

altmetric image

Publications

Mechanisms for Hydrogen-Atom Abstraction by Mononuclear Copper(III) Cores: Hydrogen-Atom Transfer or Concerted Proton-Coupled Electron Transfer?

Mandal Mukunda M   Elwell Courtney E CE   Bouchey Caitlin J CJ   Zerk Timothy J TJ   Tolman William B WB   Cramer Christopher J CJ  

Journal of the American Chemical Society 20191016 43


In a possibly biomimetic fashion, formally copper(III)-oxygen complexes LCu(III)-OH (<b>1</b>) and LCu(III)-OOCm (<b>2</b>) (L<sup>2-</sup> = <i>N</i>,<i>N</i>'-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide, Cm = α,α-dimethylbenzyl) have been shown to activate X-H bonds (X = C, O). Herein, we demonstrate similar X-H bond activation by a formally Cu(III) complex supported by the same dicarboxamido ligand, LCu(III)-O<sub>2</sub>CAr<sup>1</sup> (<b>3</b>, Ar<sup>1</sup> = <i>meta</i>-chlorop  ...[more]

Similar Datasets

| S-EPMC6563433 | biostudies-literature
| S-EPMC4311965 | biostudies-literature
| S-EPMC3818522 | biostudies-literature
| S-EPMC5812448 | biostudies-literature
| S-EPMC5812807 | biostudies-literature
| S-EPMC7517869 | biostudies-literature
| S-EPMC2518092 | biostudies-literature
| S-EPMC4477199 | biostudies-literature
| S-EPMC3102414 | biostudies-literature
| S-EPMC2867729 | biostudies-literature