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A Highly Oxidizing and Isolable Oxoruthenium(V) Complex [Ru V (N 4 O)(O)] 2+ : Electronic Structure, Redox Properties, and Oxidation Reactions Investigated by DFT Calculations
Author(s) -
Guan Xiangguo,
Chan Sharon LaiFung,
Che ChiMing
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300458
Subject(s) - chemistry , redox , oxidizing agent , molecule , cyclohexane , intermolecular force , bond cleavage , inorganic chemistry , photochemistry , crystallography , catalysis , organic chemistry
The electronic structure and redox properties of the highly oxidizing, isolable Ru V O complex [Ru V (N 4 O)(O)] 2+ , its oxidation reactions with saturated alkanes (cyclohexane and methane) and inorganic substrates ( hydrochloric acid and water), and its intermolecular coupling reaction have been examined by DFT calculations. The oxidation reactions 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 −1 , respectively. The overall free energy activation barrier (Δ G ≠ =25.5 kcal mol −1 ) of oxidation of hydrochloric acid can be decomposed into two parts: the formation of [Ru III (N 4 O)(HOCl)] 2+ (Δ G =15.0 kcal mol −1 ) and the substitution of HOCl by a water molecule (Δ G ≠ =10.5 kcal mol −1 ). For water oxidation, nucleophilic attack on Ru V O by water, leading to OO bond formation, has a free energy barrier of 24.0 kcal mol −1 , the major component of which comes from the cleavage of the HOH bond of water. Intermolecular self‐coupling of two molecules of [Ru V (N 4 O)(O)] 2+ leads to the [(N 4 O)Ru IV O 2 Ru III (N 4 O)] 4+ complex with a calculated free energy barrier of 12.0 kcal mol −1 .