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Title: Ligand Lone-Pair Influence on Hydrocarbon C-H Activation: A Computational Perspective Δ

Abstract

Mid to late transition metal complexes that break hydrocarbon C-H bonds by transferring the hydrogen to a heteroatom ligand while forming a metal-alkyl bond offer a promising strategy for C-H activation. Here we report a density functional (B3LYP, M06, and X3LYP) analysis of cis-(acac)2MX and TpM(L)X (M = Ir, Ru, Os, and Rh; acac = acetylacetonate, Tp = tris(pyrazolyl)borate; X = CH3, OH, OMe, NH2, and NMe2) systems for methane C-H bond activation reaction kinetics and thermodynamics. We address the importance of whether a ligand lone pair provides an intrinsic kinetic advantage through possible electronic dπ-pπ repulsions for M-OR and M-NR2 systems versus M-CH3 systems. This involves understanding the energetic impact of the X ligand group on ligand loss, C-H bond coordination, and C-H bond cleavage steps as well as understanding how the nucleophilicity of the ligand X group, the electrophilicity of the transition metal center, and cis-ligand stabilization effect influence each of these steps. We also explore how spectator ligands and second- versus third-row transition metal centers impact the energetics of each of these C-H activation steps.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Catalytic Hydrocarbon Functionalization (CCHF)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1382119
DOE Contract Number:  
SC0001298
Resource Type:
Journal Article
Journal Name:
Organometallics
Additional Journal Information:
Journal Volume: 29; Journal Issue: 24; Related Information: CCHF partners with University of Virginia (lead); Brigham Young University; California Institute of Technology; Colorado School of Mines; University of Maryland; University of North Carolina, Chapel Hill; University of North Texas; Princeton University; The Scripps Research Institute; Yale University; Journal ID: ISSN 0276-7333
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (homogeneous); catalysis (heterogeneous); bio-inspired; hydrogen and fuel cells; materials and chemistry by design; synthesis (novel materials)

Citation Formats

Ess, Daniel H., Gunnoe, T. Brent, Cundari, Thomas R., Goddard, William A., and Periana, Roy A. Ligand Lone-Pair Influence on Hydrocarbon C-H Activation: A Computational Perspective Δ. United States: N. p., 2010. Web. doi:10.1021/om100974q.
Ess, Daniel H., Gunnoe, T. Brent, Cundari, Thomas R., Goddard, William A., & Periana, Roy A. Ligand Lone-Pair Influence on Hydrocarbon C-H Activation: A Computational Perspective Δ. United States. doi:10.1021/om100974q.
Ess, Daniel H., Gunnoe, T. Brent, Cundari, Thomas R., Goddard, William A., and Periana, Roy A. Mon . "Ligand Lone-Pair Influence on Hydrocarbon C-H Activation: A Computational Perspective Δ". United States. doi:10.1021/om100974q.
@article{osti_1382119,
title = {Ligand Lone-Pair Influence on Hydrocarbon C-H Activation: A Computational Perspective Δ},
author = {Ess, Daniel H. and Gunnoe, T. Brent and Cundari, Thomas R. and Goddard, William A. and Periana, Roy A.},
abstractNote = {Mid to late transition metal complexes that break hydrocarbon C-H bonds by transferring the hydrogen to a heteroatom ligand while forming a metal-alkyl bond offer a promising strategy for C-H activation. Here we report a density functional (B3LYP, M06, and X3LYP) analysis of cis-(acac)2MX and TpM(L)X (M = Ir, Ru, Os, and Rh; acac = acetylacetonate, Tp = tris(pyrazolyl)borate; X = CH3, OH, OMe, NH2, and NMe2) systems for methane C-H bond activation reaction kinetics and thermodynamics. We address the importance of whether a ligand lone pair provides an intrinsic kinetic advantage through possible electronic dπ-pπ repulsions for M-OR and M-NR2 systems versus M-CH3 systems. This involves understanding the energetic impact of the X ligand group on ligand loss, C-H bond coordination, and C-H bond cleavage steps as well as understanding how the nucleophilicity of the ligand X group, the electrophilicity of the transition metal center, and cis-ligand stabilization effect influence each of these steps. We also explore how spectator ligands and second- versus third-row transition metal centers impact the energetics of each of these C-H activation steps.},
doi = {10.1021/om100974q},
journal = {Organometallics},
issn = {0276-7333},
number = 24,
volume = 29,
place = {United States},
year = {2010},
month = {12}
}