Universität zu Köln

Li, Jilai ORCID: 0000-0002-3363-9164, Zhou, Shaodong ORCID: 0000-0003-3048-4678, Zhang, Jun, Schlangen, Maria ORCID: 0000-0002-8783-6788, Usharani, Dandamudi, Shaik, Sason and Schwarz, Helmut ORCID: 0000-0002-3369-7997 (2016). Mechanistic Variants in Gas-Phase Metal-Oxide Mediated Activation of Methane at Ambient Conditions. J. Am. Chem. Soc., 138 (35). S. 11368 - 11378. WASHINGTON: AMER CHEMICAL SOC. ISSN 1520-5126

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Abstract

The C-H bond activation of methane mediated by a prototypical heteronuclear metal-oxide cluster, [Al2Mg2O5](center dot+), was investigated by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in conjunction with high-level quantum mechanical calculations. Experimentally, hydrogen-atom abstraction from methane by the cluster ion [Al2Mg2O5](center dot+) takes place at ambient conditions. As to the mechanism, according to our computational findings, both the proton-coupled electron transfer (PCET) and the conventional hydrogen-atom transfer (HAT) are feasible and compete with each other. This is in distinct contrast to the [XYO2](+) (X, Y = Mg, Al, Si) cluster oxide ions which activate methane exclusively via the PCET route (Li, J.; Zhou, S.; Zhang, J.; Schlangen, M.; Weiske, T.; Usharani, D.; Shaik, S.; Schwarz, H. J. Am. Chem. Soc. 2016, 138, 7973-7981). The electronic origins of the mechanistically rather complex reactivity scenarios of the [Al2Mg2O5](center dot+)/CH4 couple were elucidated. For the PCET mechanism, in which the Lewis acid base pair [Al+-O-] of the cluster acts as the active site, a clear correlation has been established between the nature of the transition state, the corresponding barrier height, the Lewis acidity basicity of the [M+-O-] unit, as well as the bond order of the M+-O- bond. Also addressed is the role of the spin and charge distributions of a terminal oxygen radical site in the direct HAT route. The knowledge of the factors that control the reactivity of PCET and HAT pathways not only deepens our mechanistic understanding of metal-oxide mediated C-H bond activation but may also provide guidance for the rational design of catalysts.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Li, Jilai UNSPECIFIED orcid.org/0000-0002-3363-9164 UNSPECIFIED Zhou, Shaodong UNSPECIFIED orcid.org/0000-0003-3048-4678 UNSPECIFIED Zhang, Jun UNSPECIFIED UNSPECIFIED UNSPECIFIED Schlangen, Maria UNSPECIFIED orcid.org/0000-0002-8783-6788 UNSPECIFIED Usharani, Dandamudi UNSPECIFIED UNSPECIFIED UNSPECIFIED Shaik, Sason UNSPECIFIED UNSPECIFIED UNSPECIFIED Schwarz, Helmut UNSPECIFIED orcid.org/0000-0002-3369-7997 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-262511
DOI:	10.1021/jacs.6b07246
Journal or Publication Title:	J. Am. Chem. Soc.
Volume:	138
Number:	35
Page Range:	S. 11368 - 11378
Date:	2016
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1520-5126
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language COUPLED ELECTRON-TRANSFER; HYDROGEN-ATOM TRANSFER; H BOND ACTIVATION; CHARGE-TRANSFER REACTIONS; C-H; EXCHANGE-REACTIONS; CHEMICAL-REACTIVITY; MGO NANOPARTICLES; GAMMA-ALUMINA; ACTIVE-SITES Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26251