File Download
 
Links for fulltext
(May Require Subscription)
 
Supplementary

Conference Paper: Hydrocarbon oxidation by β-halogenated dioxoruthenium(vi) porphyrin complexes: Effect of reduction potential (Ru VI/V) and C-H bond-dissociation energy on rate constants
  • Basic View
  • Metadata View
  • XML View
TitleHydrocarbon oxidation by β-halogenated dioxoruthenium(vi) porphyrin complexes: Effect of reduction potential (Ru VI/V) and C-H bond-dissociation energy on rate constants
 
AuthorsChe, CM1
Zhang, JL1
Zhang, R1
Huang, JS1
Lai, TS3
Tsui, WM1
Zhou, XG1
Zhou, ZY2
Zhu, N1
Chang, CK3
 
KeywordsElectrochemistry
Oxidation
Porphyrinoids
Ruthenium
Structure elucidation
 
Issue Date2005
 
PublisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry
 
CitationChemistry - A European Journal, 2005, v. 11 n. 23, p. 7040-7053 [How to Cite?]
DOI: http://dx.doi.org/10.1002/chem.200500814
 
Abstractβ-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru VI-(F 28-tpp)O 2] [F 28-tpp = 2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis-(pentafluorophenyl)porphyrinato(2-)] and [Ru VI(β-Br 8-tmp)O 2] [β-Br 8-tmp = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,4,6-trimethylphenyl) porphyrinato(2-)] were prepared from reactions of [Ru II(por)(CO)] [por = por-phyrinato(2-)] with m-chloroperoxybenzoic acid in CH 2Cl 2. Reactions of [Ru VI(por)O 2] with excess PPh 3 in CH 2Cl 2 gave [Ru II(F 20tpp)(PPh 3) 2] [F 20)-tpp = 5,10,15,20-tetrakis(pentafluo-rophenyl)porphyrinato(2-)] and [Ru II-(F 28-tpp)(PPh 3) 2]. The structures of [Ru II(por)(CO)(H 2O)] and [Ru II(por)-(PPh 3) 2] (por = F 20-tpp, F 28-tpp) were determined by X-ray crystallography, revealing the effect of β-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru VI(F 20-tpp)O 2] shows a Ru=O bond length of 1.718(3) Å. Electrochemical reduction of [Ru VI(por)O 2] (Ru VI to Ru V) is irreversible or quasi-reversible, with the E p.c(Ru VI/V) spanning -0.31 to -1.15V versus Cp 2Fe +/0. Kinetic studies were performed for the reactions of various [Ru VI(por)O 2], including [Ru VI-(F 28-tpp)O 2] and [Ru VI(β-Br 8-tmp)O 2], with para-substituted styrenes p-X-C 6H 4CH=CH 2 (X = H, F, Cl, Me, MeO), cis- and trans-β-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k 2) obtained for the hydrocarbon oxidations by [Ru VI-(F 28-tpp)O 2] are up to 28-fold larger than by [Ru VI(F 20-tpp)O 2]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru VI(F 28-tpp)O 2] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k 2 values for the oxidation of styrene and ethylbenzene by [Ru VI-(por)O 2] increase with E p.c(Ru VI/V), and there is a linear correlation between log k 2 and E p.c(Ru VI/V). The small slope (≈2 V -1) of the log k 2 versus E p.c(Ru VI/V) plot suggests that the extent of charge transfer is small in the rate-determining step of the hydrocarbon oxidations. The rate constants correlate well with the C-H bond dissociation energies, in favor of a hydrogen-atom abstraction mechanism. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
 
ISSN0947-6539
2012 Impact Factor: 5.831
2012 SCImago Journal Rankings: 2.438
 
DOIhttp://dx.doi.org/10.1002/chem.200500814
 
ISI Accession Number IDWOS:000233508800024
 
ReferencesReferences in Scopus
 
DC FieldValue
dc.contributor.authorChe, CM
 
dc.contributor.authorZhang, JL
 
dc.contributor.authorZhang, R
 
dc.contributor.authorHuang, JS
 
dc.contributor.authorLai, TS
 
dc.contributor.authorTsui, WM
 
dc.contributor.authorZhou, XG
 
dc.contributor.authorZhou, ZY
 
dc.contributor.authorZhu, N
 
dc.contributor.authorChang, CK
 
dc.date.accessioned2010-09-06T06:20:10Z
 
dc.date.available2010-09-06T06:20:10Z
 
dc.date.issued2005
 
dc.description.abstractβ-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru VI-(F 28-tpp)O 2] [F 28-tpp = 2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis-(pentafluorophenyl)porphyrinato(2-)] and [Ru VI(β-Br 8-tmp)O 2] [β-Br 8-tmp = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,4,6-trimethylphenyl) porphyrinato(2-)] were prepared from reactions of [Ru II(por)(CO)] [por = por-phyrinato(2-)] with m-chloroperoxybenzoic acid in CH 2Cl 2. Reactions of [Ru VI(por)O 2] with excess PPh 3 in CH 2Cl 2 gave [Ru II(F 20tpp)(PPh 3) 2] [F 20)-tpp = 5,10,15,20-tetrakis(pentafluo-rophenyl)porphyrinato(2-)] and [Ru II-(F 28-tpp)(PPh 3) 2]. The structures of [Ru II(por)(CO)(H 2O)] and [Ru II(por)-(PPh 3) 2] (por = F 20-tpp, F 28-tpp) were determined by X-ray crystallography, revealing the effect of β-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru VI(F 20-tpp)O 2] shows a Ru=O bond length of 1.718(3) Å. Electrochemical reduction of [Ru VI(por)O 2] (Ru VI to Ru V) is irreversible or quasi-reversible, with the E p.c(Ru VI/V) spanning -0.31 to -1.15V versus Cp 2Fe +/0. Kinetic studies were performed for the reactions of various [Ru VI(por)O 2], including [Ru VI-(F 28-tpp)O 2] and [Ru VI(β-Br 8-tmp)O 2], with para-substituted styrenes p-X-C 6H 4CH=CH 2 (X = H, F, Cl, Me, MeO), cis- and trans-β-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k 2) obtained for the hydrocarbon oxidations by [Ru VI-(F 28-tpp)O 2] are up to 28-fold larger than by [Ru VI(F 20-tpp)O 2]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru VI(F 28-tpp)O 2] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k 2 values for the oxidation of styrene and ethylbenzene by [Ru VI-(por)O 2] increase with E p.c(Ru VI/V), and there is a linear correlation between log k 2 and E p.c(Ru VI/V). The small slope (≈2 V -1) of the log k 2 versus E p.c(Ru VI/V) plot suggests that the extent of charge transfer is small in the rate-determining step of the hydrocarbon oxidations. The rate constants correlate well with the C-H bond dissociation energies, in favor of a hydrogen-atom abstraction mechanism. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
 
dc.description.natureLink_to_subscribed_fulltext
 
dc.identifier.citationChemistry - A European Journal, 2005, v. 11 n. 23, p. 7040-7053 [How to Cite?]
DOI: http://dx.doi.org/10.1002/chem.200500814
 
dc.identifier.doihttp://dx.doi.org/10.1002/chem.200500814
 
dc.identifier.epage7053
 
dc.identifier.hkuros117999
 
dc.identifier.isiWOS:000233508800024
 
dc.identifier.issn0947-6539
2012 Impact Factor: 5.831
2012 SCImago Journal Rankings: 2.438
 
dc.identifier.issue23
 
dc.identifier.openurl
 
dc.identifier.pmid16163758
 
dc.identifier.scopuseid_2-s2.0-27944472608
 
dc.identifier.spage7040
 
dc.identifier.urihttp://hdl.handle.net/10722/70148
 
dc.identifier.volume11
 
dc.languageeng
 
dc.publisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry
 
dc.publisher.placeGermany
 
dc.relation.ispartofChemistry - A European Journal
 
dc.relation.referencesReferences in Scopus
 
dc.subjectElectrochemistry
 
dc.subjectOxidation
 
dc.subjectPorphyrinoids
 
dc.subjectRuthenium
 
dc.subjectStructure elucidation
 
dc.titleHydrocarbon oxidation by β-halogenated dioxoruthenium(vi) porphyrin complexes: Effect of reduction potential (Ru VI/V) and C-H bond-dissociation energy on rate constants
 
dc.typeConference_Paper
 
<?xml encoding="utf-8" version="1.0"?>
<item><contributor.author>Che, CM</contributor.author>
<contributor.author>Zhang, JL</contributor.author>
<contributor.author>Zhang, R</contributor.author>
<contributor.author>Huang, JS</contributor.author>
<contributor.author>Lai, TS</contributor.author>
<contributor.author>Tsui, WM</contributor.author>
<contributor.author>Zhou, XG</contributor.author>
<contributor.author>Zhou, ZY</contributor.author>
<contributor.author>Zhu, N</contributor.author>
<contributor.author>Chang, CK</contributor.author>
<date.accessioned>2010-09-06T06:20:10Z</date.accessioned>
<date.available>2010-09-06T06:20:10Z</date.available>
<date.issued>2005</date.issued>
<identifier.citation>Chemistry - A European Journal, 2005, v. 11 n. 23, p. 7040-7053</identifier.citation>
<identifier.issn>0947-6539</identifier.issn>
<identifier.uri>http://hdl.handle.net/10722/70148</identifier.uri>
<description.abstract>&#946;-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru VI-(F 28-tpp)O 2] [F 28-tpp = 2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis-(pentafluorophenyl)porphyrinato(2-)] and [Ru VI(&#946;-Br 8-tmp)O 2] [&#946;-Br 8-tmp = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,4,6-trimethylphenyl) porphyrinato(2-)] were prepared from reactions of [Ru II(por)(CO)] [por = por-phyrinato(2-)] with m-chloroperoxybenzoic acid in CH 2Cl 2. Reactions of [Ru VI(por)O 2] with excess PPh 3 in CH 2Cl 2 gave [Ru II(F 20tpp)(PPh 3) 2] [F 20)-tpp = 5,10,15,20-tetrakis(pentafluo-rophenyl)porphyrinato(2-)] and [Ru II-(F 28-tpp)(PPh 3) 2]. The structures of [Ru II(por)(CO)(H 2O)] and [Ru II(por)-(PPh 3) 2] (por = F 20-tpp, F 28-tpp) were determined by X-ray crystallography, revealing the effect of &#946;-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru VI(F 20-tpp)O 2] shows a Ru=O bond length of 1.718(3) &#197;. Electrochemical reduction of [Ru VI(por)O 2] (Ru VI to Ru V) is irreversible or quasi-reversible, with the E p.c(Ru VI/V) spanning -0.31 to -1.15V versus Cp 2Fe +/0. Kinetic studies were performed for the reactions of various [Ru VI(por)O 2], including [Ru VI-(F 28-tpp)O 2] and [Ru VI(&#946;-Br 8-tmp)O 2], with para-substituted styrenes p-X-C 6H 4CH=CH 2 (X = H, F, Cl, Me, MeO), cis- and trans-&#946;-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k 2) obtained for the hydrocarbon oxidations by [Ru VI-(F 28-tpp)O 2] are up to 28-fold larger than by [Ru VI(F 20-tpp)O 2]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru VI(F 28-tpp)O 2] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k 2 values for the oxidation of styrene and ethylbenzene by [Ru VI-(por)O 2] increase with E p.c(Ru VI/V), and there is a linear correlation between log k 2 and E p.c(Ru VI/V). The small slope (&#8776;2 V -1) of the log k 2 versus E p.c(Ru VI/V) plot suggests that the extent of charge transfer is small in the rate-determining step of the hydrocarbon oxidations. The rate constants correlate well with the C-H bond dissociation energies, in favor of a hydrogen-atom abstraction mechanism. &#169; 2005 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.</description.abstract>
<language>eng</language>
<publisher>Wiley - V C H Verlag GmbH &amp; Co KGaA. The Journal&apos;s web site is located at http://www.wiley-vch.de/home/chemistry</publisher>
<relation.ispartof>Chemistry - A European Journal</relation.ispartof>
<subject>Electrochemistry</subject>
<subject>Oxidation</subject>
<subject>Porphyrinoids</subject>
<subject>Ruthenium</subject>
<subject>Structure elucidation</subject>
<title>Hydrocarbon oxidation by &#946;-halogenated dioxoruthenium(vi) porphyrin complexes: Effect of reduction potential (Ru VI/V) and C-H bond-dissociation energy on rate constants</title>
<type>Conference_Paper</type>
<identifier.openurl>http://library.hku.hk:4550/resserv?sid=HKU:IR&amp;issn=0947-6539&amp;volume=11&amp;issue=23&amp;spage=7040&amp;epage=7053&amp;date=2005&amp;atitle=Hydrocarbon+oxidation+by+&#946;-halogenated+dioxoruthenium+(VI)+porphyrin+camplexes:+effect+of+reduction+potential+(RuVI/V)+and+C-H+bond-dissociation+energy+on+rate+constants</identifier.openurl>
<description.nature>Link_to_subscribed_fulltext</description.nature>
<identifier.doi>10.1002/chem.200500814</identifier.doi>
<identifier.pmid>16163758</identifier.pmid>
<identifier.scopus>eid_2-s2.0-27944472608</identifier.scopus>
<identifier.hkuros>117999</identifier.hkuros>
<relation.references>http://www.scopus.com/mlt/select.url?eid=2-s2.0-27944472608&amp;selection=ref&amp;src=s&amp;origin=recordpage</relation.references>
<identifier.volume>11</identifier.volume>
<identifier.issue>23</identifier.issue>
<identifier.spage>7040</identifier.spage>
<identifier.epage>7053</identifier.epage>
<identifier.isi>WOS:000233508800024</identifier.isi>
<publisher.place>Germany</publisher.place>
</item>
Author Affiliations
  1. Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong
  2. Hong Kong Polytechnic University
  3. Hong Kong University of Science and Technology