Privileged Role of Thiolate as the Axial Ligand in Hydrogen Atom Transfer Reactions by Oxoiron(IV) Complexes in Shaping the Potential Energy Surface and Inducing Significant H-Atom Tunneling

Johannes E.M.N. Klein, Debasish Mandal, Wei Min Ching, Dibyendu Mallick, Lawrence Que, Sason Shaik

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

An H/D kinetic isotope effect (KIE) of 80 is found at -20 °C for the oxidation of 9,10-dihydroanthracene by [FeIV(O)(TMCS)]+, a complex supported by the tetramethylcyclam (TMC) macrocycle with a tethered thiolate. This KIE value approaches that previously predicted by DFT calculations. Other [FeIV(O)(TMC)(anion)] complexes exhibit values of 20, suggesting that the thiolate ligand of [FeIV(O)(TMCS)]+ plays a unique role in facilitating tunneling. Calculations show that tunneling is most enhanced (a) when the bond asymmetry between C-H bond breaking and O-H bond formation in the transition state is minimized, and (b) when the electrostatic interactions in the O - -H - -C moiety are maximal. These two factors - which peak for the best electron donor, the thiolate ligand - afford a slim and narrow barrier through which the H-atom can tunnel most effectively.

Original languageEnglish (US)
Pages (from-to)18705-18713
Number of pages9
JournalJournal of the American Chemical Society
Volume139
Issue number51
DOIs
StatePublished - Dec 27 2017

Fingerprint

Potential energy surfaces
Isotopes
Hydrogen
Ligands
Atoms
Kinetics
Coulomb interactions
Static Electricity
Discrete Fourier transforms
Anions
Tunnels
Negative ions
Electrons
Oxidation
(FeIV(O)(TMCS))+

Cite this

Privileged Role of Thiolate as the Axial Ligand in Hydrogen Atom Transfer Reactions by Oxoiron(IV) Complexes in Shaping the Potential Energy Surface and Inducing Significant H-Atom Tunneling. / Klein, Johannes E.M.N.; Mandal, Debasish; Ching, Wei Min; Mallick, Dibyendu; Que, Lawrence; Shaik, Sason.

In: Journal of the American Chemical Society, Vol. 139, No. 51, 27.12.2017, p. 18705-18713.

Research output: Contribution to journalArticle

@article{5c9355c5d6d845c0a0df5aba0e9db15d,
title = "Privileged Role of Thiolate as the Axial Ligand in Hydrogen Atom Transfer Reactions by Oxoiron(IV) Complexes in Shaping the Potential Energy Surface and Inducing Significant H-Atom Tunneling",
abstract = "An H/D kinetic isotope effect (KIE) of 80 is found at -20 °C for the oxidation of 9,10-dihydroanthracene by [FeIV(O)(TMCS)]+, a complex supported by the tetramethylcyclam (TMC) macrocycle with a tethered thiolate. This KIE value approaches that previously predicted by DFT calculations. Other [FeIV(O)(TMC)(anion)] complexes exhibit values of 20, suggesting that the thiolate ligand of [FeIV(O)(TMCS)]+ plays a unique role in facilitating tunneling. Calculations show that tunneling is most enhanced (a) when the bond asymmetry between C-H bond breaking and O-H bond formation in the transition state is minimized, and (b) when the electrostatic interactions in the O - -H - -C moiety are maximal. These two factors - which peak for the best electron donor, the thiolate ligand - afford a slim and narrow barrier through which the H-atom can tunnel most effectively.",
author = "Klein, {Johannes E.M.N.} and Debasish Mandal and Ching, {Wei Min} and Dibyendu Mallick and Lawrence Que and Sason Shaik",
year = "2017",
month = "12",
day = "27",
doi = "10.1021/jacs.7b11300",
language = "English (US)",
volume = "139",
pages = "18705--18713",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "51",

}

TY - JOUR

T1 - Privileged Role of Thiolate as the Axial Ligand in Hydrogen Atom Transfer Reactions by Oxoiron(IV) Complexes in Shaping the Potential Energy Surface and Inducing Significant H-Atom Tunneling

AU - Klein, Johannes E.M.N.

AU - Mandal, Debasish

AU - Ching, Wei Min

AU - Mallick, Dibyendu

AU - Que, Lawrence

AU - Shaik, Sason

PY - 2017/12/27

Y1 - 2017/12/27

N2 - An H/D kinetic isotope effect (KIE) of 80 is found at -20 °C for the oxidation of 9,10-dihydroanthracene by [FeIV(O)(TMCS)]+, a complex supported by the tetramethylcyclam (TMC) macrocycle with a tethered thiolate. This KIE value approaches that previously predicted by DFT calculations. Other [FeIV(O)(TMC)(anion)] complexes exhibit values of 20, suggesting that the thiolate ligand of [FeIV(O)(TMCS)]+ plays a unique role in facilitating tunneling. Calculations show that tunneling is most enhanced (a) when the bond asymmetry between C-H bond breaking and O-H bond formation in the transition state is minimized, and (b) when the electrostatic interactions in the O - -H - -C moiety are maximal. These two factors - which peak for the best electron donor, the thiolate ligand - afford a slim and narrow barrier through which the H-atom can tunnel most effectively.

AB - An H/D kinetic isotope effect (KIE) of 80 is found at -20 °C for the oxidation of 9,10-dihydroanthracene by [FeIV(O)(TMCS)]+, a complex supported by the tetramethylcyclam (TMC) macrocycle with a tethered thiolate. This KIE value approaches that previously predicted by DFT calculations. Other [FeIV(O)(TMC)(anion)] complexes exhibit values of 20, suggesting that the thiolate ligand of [FeIV(O)(TMCS)]+ plays a unique role in facilitating tunneling. Calculations show that tunneling is most enhanced (a) when the bond asymmetry between C-H bond breaking and O-H bond formation in the transition state is minimized, and (b) when the electrostatic interactions in the O - -H - -C moiety are maximal. These two factors - which peak for the best electron donor, the thiolate ligand - afford a slim and narrow barrier through which the H-atom can tunnel most effectively.

UR - http://www.scopus.com/inward/record.url?scp=85037574149&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85037574149&partnerID=8YFLogxK

U2 - 10.1021/jacs.7b11300

DO - 10.1021/jacs.7b11300

M3 - Article

C2 - 29179544

AN - SCOPUS:85037574149

VL - 139

SP - 18705

EP - 18713

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 51

ER -