title: Mechanistic insights into the reactions of hydride transfer versus hydrogen atom transfer by a trans-dioxoruthenium(VI) complex.
abstract: A mononuclear high-valent trans-dioxoruthenium(VI) complex, trans-[Ru(VI)(TMC)(O)2](2+) (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), was synthesized and characterized by various spectroscopic techniques and X-ray crystallography. The reactivity of the trans-[Ru(VI)(TMC)(O)2](2+) complex was investigated in hydride transfer and hydrogen atom transfer reactions. The mechanism of hydride transfer from dihydronicotinamide adenine dinucleotide (NADH) analogues to trans-[Ru(VI)(TMC)(O)2](2+), which proceeds via a proton-coupled electron transfer (PCET), followed by a rapid electron transfer (ET), has been proposed by the observation of a good linear correlation between the log rate constants of trans-[Ru(VI)(TMC)(O)2](2+) and p-chloranil (Cl4Q) and a large kinetic isotope effect (KIE) value of 13(1). In the case of the oxidation of alkyl hydrocarbons by the trans-[Ru(VI)(TMC)(O)2](2+) complex, the second-order rate constants were dependent on the C-H bond dissociation energy (BDE) of the substrates, and a large KIE value of 26(2) was obtained in the oxidation of xanthene and deuterated xanthene-d2 by the trans-[Ru(VI)(TMC)(O)2](2+) complex, indicating that the C-H bond activation of alkyl hydrocarbons proceeds via an H-atom abstraction in the rate-determining step.
authors: Department of Chemistry and Nano Science, Center for Biomimetic System, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors: Sunder N
authors: SN
authors: Dhuri
authors: Yong-Min
authors: YM
authors: Lee
authors: Mi Sook
authors: MS
authors: Seo
authors: Jaeheung
authors: J
authors: Cho
authors: Dattaprasad D
authors: DD
authors: Narulkar
authors: Shunichi
authors: S
authors: Fukuzumi
authors: Wonwoo
authors: W
authors: Nam
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D004579:Electron Transport; D006859:Hydrogen / Q000737:chemistry*; D007536:Isomerism; D009243:NAD / Q000737:chemistry; D010084:Oxidation-Reduction; D011522:Protons; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014966:Xanthenes / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D011522:Protons; D014966:Xanthenes; D009243:NAD; D012428:Ruthenium; D006859:Hydrogen