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Article: Proton-coupled electron-transfer reactions. Mechanisms of two-electron reduction of trans-dioxoruthenium(VI) to trans-aquooxoruthenium(VI) and disproportionate of trans-dioxoruthenium(V)

TitleProton-coupled electron-transfer reactions. Mechanisms of two-electron reduction of trans-dioxoruthenium(VI) to trans-aquooxoruthenium(VI) and disproportionate of trans-dioxoruthenium(V)
Authors
Issue Date1990
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html
Citation
Journal Of The American Chemical Society, 1990, v. 112 n. 13, p. 5176-5181 How to Cite?
AbstractThe kinetics and mechanism of the reduction of trans-[Ru vI(TMC)(O) 2] 2+ to trans-[Ru Iv(TMC)O(H 2O)] 2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) in aqueous solution by outer-sphere one-electron reductants (R), trans-[Ru VI(TMC)(O) 2] 2+ + 2R + 2H + → trans-[Ru Iv(TMC)O(H 2O)] 2+ + 2R +, have been studied. The first step of the reduction is a simple outer-sphere electron-transfer process, trans-[Ru VI(TMC)(O) 2] 2+ + R → trans-[Ru v(TMC)(O) 2] + + R + with rate = k 2[Ru(VI)] [R]. The rate constants (k 2) with cis-[Ru II(NH 3) 4bpy] 2+ (bpy = 2,2′-bipyridine), [Ru II(NH 3) 5isn] 2+ (isn = isonicotinamide), and [Ru II(NH 3) 5py] 2+ (py = pyridine) have been measured and can be correlated with the Marcus cross relation. The estimated self-exchange rate constant of the trans-[Ru VI(TMC)(O) 2] 2+/ trans-[Ru v(TMC)(O) 2]+ couple is 1.5 × 10 5 mol -1 dm 3 s -1 (I = 0.1 M) at 298 K. When trans-[Ru VI(TMC)(O) 2] 2+ is in excess, the trans-[Ru V(TMC)(O) 2]+ species formed will undergo rapid disproportionation, 2trans-[Ru v(TMC)(O) 2] + + 2H + → trans-[Ru VI(TMC)(O) 2] 2+ + trans-[Ru IV(TMC)O(H 2O)] 2+. The disproportionation follows the rate law: rate = K dis[Ru(V)] 2 with K dis = 2k eK p[H +]/(1 + K p[H +]) 2. The K p and k e are referred to the equilibrium constant and rate constant for the respective reactions, trans-[Ru v(TMC)(O) 2] 2+ + H +⇄ trans-[Ru v(TMC)O(OH)] 2+ and trans-(Ru v(TMC)O(OH)] 2+ + trans-[Ru v(TMC)(O) 2] + → trans-[Ru VI(TMC)(O) 2] 2+ + trans-[Ru IV(TMC)O(OH)] +. At 299 K and I = 0.1 M, K p and k c have been determined to be 615 ± 50 mol -1 dm 3 and (2.72 ± 0.34) × 10 6 mol -1 dm 3 s -1, respectively. The self-exchange rate constant of the trans-[Ru v(TMC)O(OH)] 2+/trans-[Ru IV(TMC)O(OH)] + has been estimated to be 5 × 10 3 mol -1 dm 3 s -1 at 298 K and I = 0.1 M.
Persistent Identifierhttp://hdl.handle.net/10722/167378
ISSN
2015 Impact Factor: 13.038
2015 SCImago Journal Rankings: 7.123
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DC FieldValueLanguage
dc.contributor.authorChe, CMen_US
dc.contributor.authorLau, Ken_US
dc.contributor.authorLau, TCen_US
dc.contributor.authorPoon, CKen_US
dc.date.accessioned2012-10-08T03:06:14Z-
dc.date.available2012-10-08T03:06:14Z-
dc.date.issued1990en_US
dc.identifier.citationJournal Of The American Chemical Society, 1990, v. 112 n. 13, p. 5176-5181en_US
dc.identifier.issn0002-7863en_US
dc.identifier.urihttp://hdl.handle.net/10722/167378-
dc.description.abstractThe kinetics and mechanism of the reduction of trans-[Ru vI(TMC)(O) 2] 2+ to trans-[Ru Iv(TMC)O(H 2O)] 2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) in aqueous solution by outer-sphere one-electron reductants (R), trans-[Ru VI(TMC)(O) 2] 2+ + 2R + 2H + → trans-[Ru Iv(TMC)O(H 2O)] 2+ + 2R +, have been studied. The first step of the reduction is a simple outer-sphere electron-transfer process, trans-[Ru VI(TMC)(O) 2] 2+ + R → trans-[Ru v(TMC)(O) 2] + + R + with rate = k 2[Ru(VI)] [R]. The rate constants (k 2) with cis-[Ru II(NH 3) 4bpy] 2+ (bpy = 2,2′-bipyridine), [Ru II(NH 3) 5isn] 2+ (isn = isonicotinamide), and [Ru II(NH 3) 5py] 2+ (py = pyridine) have been measured and can be correlated with the Marcus cross relation. The estimated self-exchange rate constant of the trans-[Ru VI(TMC)(O) 2] 2+/ trans-[Ru v(TMC)(O) 2]+ couple is 1.5 × 10 5 mol -1 dm 3 s -1 (I = 0.1 M) at 298 K. When trans-[Ru VI(TMC)(O) 2] 2+ is in excess, the trans-[Ru V(TMC)(O) 2]+ species formed will undergo rapid disproportionation, 2trans-[Ru v(TMC)(O) 2] + + 2H + → trans-[Ru VI(TMC)(O) 2] 2+ + trans-[Ru IV(TMC)O(H 2O)] 2+. The disproportionation follows the rate law: rate = K dis[Ru(V)] 2 with K dis = 2k eK p[H +]/(1 + K p[H +]) 2. The K p and k e are referred to the equilibrium constant and rate constant for the respective reactions, trans-[Ru v(TMC)(O) 2] 2+ + H +⇄ trans-[Ru v(TMC)O(OH)] 2+ and trans-(Ru v(TMC)O(OH)] 2+ + trans-[Ru v(TMC)(O) 2] + → trans-[Ru VI(TMC)(O) 2] 2+ + trans-[Ru IV(TMC)O(OH)] +. At 299 K and I = 0.1 M, K p and k c have been determined to be 615 ± 50 mol -1 dm 3 and (2.72 ± 0.34) × 10 6 mol -1 dm 3 s -1, respectively. The self-exchange rate constant of the trans-[Ru v(TMC)O(OH)] 2+/trans-[Ru IV(TMC)O(OH)] + has been estimated to be 5 × 10 3 mol -1 dm 3 s -1 at 298 K and I = 0.1 M.en_US
dc.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.htmlen_US
dc.relation.ispartofJournal of the American Chemical Societyen_US
dc.titleProton-coupled electron-transfer reactions. Mechanisms of two-electron reduction of trans-dioxoruthenium(VI) to trans-aquooxoruthenium(VI) and disproportionate of trans-dioxoruthenium(V)en_US
dc.typeArticleen_US
dc.identifier.emailChe, CM:cmche@hku.hken_US
dc.identifier.authorityChe, CM=rp00670en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1021/ja00169a027-
dc.identifier.scopuseid_2-s2.0-0003444185en_US
dc.identifier.volume112en_US
dc.identifier.issue13en_US
dc.identifier.spage5176en_US
dc.identifier.epage5181en_US
dc.identifier.isiWOS:A1990DK85500027-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridChe, CM=7102442791en_US
dc.identifier.scopusauthoridLau, K=55025754200en_US
dc.identifier.scopusauthoridLau, TC=7102222310en_US
dc.identifier.scopusauthoridPoon, CK=7202673504en_US

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