CaltechAUTHORS
  A Caltech Library Service

Probing the C-O bond-formation step in metalloporphyrin catalyzed C-H oxygenation reactions

Liu, Wei and Cheng, Mu-Jeng and Nielsen, Robert J. and Goddard, William A., III and Groves, John T. (2017) Probing the C-O bond-formation step in metalloporphyrin catalyzed C-H oxygenation reactions. ACS Catalysis, 7 (6). pp. 4182-4188. ISSN 2155-5435. https://resolver.caltech.edu/CaltechAUTHORS:20170515-132737377

[img] PDF - Accepted Version
See Usage Policy.

1029Kb
[img] PDF (Experimental and computational details, supplementary figures and tables) - Supplemental Material
See Usage Policy.

1963Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20170515-132737377

Abstract

The oxygen rebound mechanism, proposed four decades ago, is invoked in a wide range of oxygen and hetero-atom transfer reactions. In this process, a high-valent metal-oxo species abstracts a hydrogen atom from the substrate to generate a carbon-centered radical, which immediately recombines with the hydroxometal intermediate with very fast rate constants that can be in the ns to ps regime. In addition to catalyzing C-O bond formation, we found that manganese porphyrins can also directly catalyze C-H halogenations and pseudohalogenations, including chlorination, bromination and fluorination as well as C-H azidation. For these cases, we showed that long-lived substrate radicals are involved, indicating that radical rebound may involve a barrier in some cases. In this study, we show that axial ligands significantly affect the oxygen rebound rate. Fluoride, hydroxide and oxo ligands all slow down the oxygen rebound rate by factors of 10-40 fold. The oxidation of norcarane by a manganese porphyrin coordinated with fluoride or hydroxide leads to the formation of significant amounts of radical rearranged products. Cis-decalin oxidation afforded both cis- and trans-decalol. Xanthene afforded dioxygen trapped products and the radical dimer product, bixanthene, under aerobic and anaerobic conditions, respectively. DFT calculations probing the rebound step show that the rebound barrier increases significantly (by 3.3, 5.4 and 6.0 kcal/mol, respectively) with fluoride, hydroxide and oxo as axial ligands.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/acscatal.7b00655DOIArticle
http://pubs.acs.org/doi/abs/10.1021/acscatal.7b00655PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/acscatal.7b00655PublisherSupporting Information
ORCID:
AuthorORCID
Liu, Wei0000-0001-6249-3179
Cheng, Mu-Jeng0000-0002-8121-0485
Nielsen, Robert J.0000-0002-7962-0186
Goddard, William A., III0000-0003-0097-5716
Groves, John T.0000-0002-9944-5899
Additional Information:© 2017 American Chemical Society. Received: February 27, 2017; Revised: May 4, 2017; Published: May 10, 2017. Supported initially by the Center for Catalytic Hydrocarbon Functionalization, an Energy Frontier Research Center, U.S. Department of Energy, Office of Science, BES, under award number DE-SC0001298 to WAG and JTG and completed with support from the US National Science Foundation (CHE-1464578 to JTG, CHE 1214158 to WAG). MJC acknowledges the financial support from the Ministry of Science and Technology of the Republic of China, under grant no. MOST 105-2113-M-006-017-MY2.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0001298
NSFCHE-1464578
NSFCHE-1214158
Ministry of Science and Technology (Taipei)MOST 105-2113-M-006-017-MY2
Subject Keywords:oxygen rebound, manganese porphyrin, iron porphyrin, heterorebound catalysis, DFT
Issue or Number:6
Record Number:CaltechAUTHORS:20170515-132737377
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170515-132737377
Official Citation:Probing the C–O Bond-Formation Step in Metalloporphyrin-Catalyzed C–H Oxygenation Reactions Wei Liu, Mu-Jeng Cheng, Robert J. Nielsen, William A. Goddard, III, and John T. Groves ACS Catalysis 2017 7 (6), 4182-4188 DOI: 10.1021/acscatal.7b00655
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77458
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:15 May 2017 23:57
Last Modified:03 Oct 2019 17:57

Repository Staff Only: item control page