A Highly Oxidizing and Isolable Oxoruthenium(V) Complex [RuV(N4O)(O)]2+: Electronic Structure, Redox Properties, and Oxidation Reactions Investigated by DFT Calculations. Issue 9 (20th June 2013)

• Record Type: Journal Article
• Authors: Guan, Xiangguo; Chan, Sharon Lai‐Fung; Che, Chi‐Ming
• Is Part Of: Chemistry, an Asian journal. Volume 8:Issue 9(2013:Sep.)
• Page Start: 2046
• Page End: 2056
• Publication Date: 2013-06-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201300458
• Languages: English
• ISSNs: 1861-4728

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The electronic structure and redox properties of the highly oxidizing, isolable Ru<sup>V</sup>O complex [Ru<sup>V</sup>(N<sub>4</sub>O)(O)]<sup>2+</sup>, its <named-content id="d410e425" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">oxidation reactions</named-content> with saturated alkanes (cyclohexane and methane) and inorganic substrates (<named-content id="d410e429" content-type="chemicalTechnology" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">hydrochloric acid</named-content> and water), and its <named-content id="d410e432" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">intermolecular</named-content><named-content id="d410e435" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">coupling reaction</named-content> have been examined by DFT calculations. The <named-content id="d410e438" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">oxidation reactions</named-content> with cyclohexane and methane proceed through hydrogen atom transfer in a transition state with a calculated free energy barrier of 10.8 and 23.8 kcal mol<sup>−1</sup>, respectively. The overall free energy activation barrier (Δ<italic>G</italic><sup>≠</sup>=25.5 kcal mol<sup>−1</sup>) of oxidation of <named-content id="d410e453" content-type="chemicalTechnology" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">hydrochloric acid</named-content> can be decomposed into two parts: the formation of [Ru<sup>III</sup>(N<sub>4</sub>O)(HOCl)]<sup>2+</sup> (Δ<italic>G</italic>=15.0 kcal mol<sup>−1</sup>) and the substitution of HOCl by a water molecule (Δ<italic>G</italic><sup>≠</sup>=10.5 kcal mol<sup>−1</sup>). For water oxidation, <named-content id="d410e480" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">nucleophilic</named-content> attack on Ru<sup>V</sup>O by water, leading to OO bond formation, has a free energy barrier of 24.0 kcal mol<sup>−1</sup>, the major component of which comes from the cleavage of the HOH bond of water. <named-content id="d410e490" content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">Intermolecular</named-content> self‐coupling of two molecules of [Ru<sup>V</sup>(N<sub>4</sub>O)(O)]<sup>2+</sup> leads to the [(N<sub>4</sub>O)Ru<sup>IV</sup>O<sub>2</sub>Ru<sup>III</sup>(N<sub>4</sub>O)]<sup>4+</sup> complex with a calculated free energy barrier of 12.0 kcal mol<sup>−1</sup>.</p> </abstract>