File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Saddle-shaped dioxo-ruthenium(VI) and -osmium(VI) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2dpp) complexes. Synthesis, spectral characterisation and alkene oxidation by [RuVI(dpp)O2]

TitleSaddle-shaped dioxo-ruthenium(VI) and -osmium(VI) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2dpp) complexes. Synthesis, spectral characterisation and alkene oxidation by [RuVI(dpp)O2]
Authors
Issue Date1998
PublisherRoyal Society of Chemistry. The Journal's web site is located at http://www.rsc.org/dalton
Citation
Journal Of The Chemical Society - Dalton Transactions, 1998 n. 11, p. 1805-1812 How to Cite?
AbstractAn improved procedure for the preparation of the saddle-distorted porphyrin 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2dpp) (yield = 75%) based on the Suzuki cross-coupling reaction between phenylboronic acid PhB(OH)2 and [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin] has been developed. X-Ray diffraction studies of [MII(dpp)(CO)(py)] (M = Ru 1 or Os 3) showed that 1 and 3 are isostructural, and the porphyrin macrocycles exhibit severe out-of-plane saddle and ruffle distortions. In both 1 and 3 the pyrrole rings are alternately tilted up and down with respect to the least-squares plane of the 25-atom porphyrin core, and the pyrrole carbons experience an average displacement of 0.769 Å from the least-squares plane compared to 0.78 Å for free H2dpp, whereas the Ru and Os atoms are displaced by 0.1006 and 0.0792 Å from the 25-atom porphyrin core respectively. The complex [RuVI(dpp)O2] 2, prepared by m-chloroperoxybenzoic acid oxidation, is an active oxidant for alkene epoxidations. In CH2Cl2 [containing 2%(w/w) pyrazole], styrene, norbornene and cis-stilbene were oxidised selectively to their respective epoxides in excellent yield. Complete stereoretention was observed for the oxidation of cis-stilbene, however oxidation of cis-β-methylstyrene afforded significant amounts of trans-epoxide suggesting that a carboradical mechanism is operative. The crystal structure of the complex [RuIV(dpp)(pz)2] (5), the product of the stoichiometric alkene oxidations, was determined. Magnetic susceptibility measurement (μeff = 3.24 μB) suggests the formulation of RuIV with two unpaired electrons in its electronic ground state. The Ru-N (pz) bond distances are 2.022(13) and 2.083(12) Å. The reactions of 2 with alkenes in CH2Cl2 (with 2% Hpz) follow second-order kinetics: rate = k1[2][alkene]. For norbornene and styrene, the second-order rate constants, k1, in CH2Cl2 at 25.9°C are (3.79 ± 0.04) × 10-3 and (4.78 ± 0.09) × 10-3 dm3 mol-1 s-1 respectively.
Persistent Identifierhttp://hdl.handle.net/10722/70186
ISSN
1999 Impact Factor: 2.31
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLiu, CJen_HK
dc.contributor.authorYu, WYen_HK
dc.contributor.authorPeng, SMen_HK
dc.contributor.authorMak, TCWen_HK
dc.contributor.authorChe, CMen_HK
dc.date.accessioned2010-09-06T06:20:31Z-
dc.date.available2010-09-06T06:20:31Z-
dc.date.issued1998en_HK
dc.identifier.citationJournal Of The Chemical Society - Dalton Transactions, 1998 n. 11, p. 1805-1812en_HK
dc.identifier.issn0300-9246en_HK
dc.identifier.urihttp://hdl.handle.net/10722/70186-
dc.description.abstractAn improved procedure for the preparation of the saddle-distorted porphyrin 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2dpp) (yield = 75%) based on the Suzuki cross-coupling reaction between phenylboronic acid PhB(OH)2 and [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin] has been developed. X-Ray diffraction studies of [MII(dpp)(CO)(py)] (M = Ru 1 or Os 3) showed that 1 and 3 are isostructural, and the porphyrin macrocycles exhibit severe out-of-plane saddle and ruffle distortions. In both 1 and 3 the pyrrole rings are alternately tilted up and down with respect to the least-squares plane of the 25-atom porphyrin core, and the pyrrole carbons experience an average displacement of 0.769 Å from the least-squares plane compared to 0.78 Å for free H2dpp, whereas the Ru and Os atoms are displaced by 0.1006 and 0.0792 Å from the 25-atom porphyrin core respectively. The complex [RuVI(dpp)O2] 2, prepared by m-chloroperoxybenzoic acid oxidation, is an active oxidant for alkene epoxidations. In CH2Cl2 [containing 2%(w/w) pyrazole], styrene, norbornene and cis-stilbene were oxidised selectively to their respective epoxides in excellent yield. Complete stereoretention was observed for the oxidation of cis-stilbene, however oxidation of cis-β-methylstyrene afforded significant amounts of trans-epoxide suggesting that a carboradical mechanism is operative. The crystal structure of the complex [RuIV(dpp)(pz)2] (5), the product of the stoichiometric alkene oxidations, was determined. Magnetic susceptibility measurement (μeff = 3.24 μB) suggests the formulation of RuIV with two unpaired electrons in its electronic ground state. The Ru-N (pz) bond distances are 2.022(13) and 2.083(12) Å. The reactions of 2 with alkenes in CH2Cl2 (with 2% Hpz) follow second-order kinetics: rate = k1[2][alkene]. For norbornene and styrene, the second-order rate constants, k1, in CH2Cl2 at 25.9°C are (3.79 ± 0.04) × 10-3 and (4.78 ± 0.09) × 10-3 dm3 mol-1 s-1 respectively.en_HK
dc.languageengen_HK
dc.publisherRoyal Society of Chemistry. The Journal's web site is located at http://www.rsc.org/daltonen_HK
dc.relation.ispartofJournal of the Chemical Society - Dalton Transactionsen_HK
dc.titleSaddle-shaped dioxo-ruthenium(VI) and -osmium(VI) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2dpp) complexes. Synthesis, spectral characterisation and alkene oxidation by [RuVI(dpp)O2]en_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1472-7773&volume=&spage=1805&epage=1812&date=1998&atitle=Saddle-shaped+dioxo-ruthenium(VI)+and+-osmium(VI)+2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin+(H2dpp)+complexes.++Synthesis,+spectral+characterisation+and+alkene+oxidation+by+[RuVI(dpp)O2]en_HK
dc.identifier.emailChe, CM:cmche@hku.hken_HK
dc.identifier.authorityChe, CM=rp00670en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1039/A800535D-
dc.identifier.scopuseid_2-s2.0-33748491047en_HK
dc.identifier.hkuros32043en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33748491047&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.issue11en_HK
dc.identifier.spage1805en_HK
dc.identifier.epage1812en_HK
dc.identifier.isiWOS:000074247500013-
dc.identifier.scopusauthoridLiu, CJ=7409788746en_HK
dc.identifier.scopusauthoridYu, WY=7403913673en_HK
dc.identifier.scopusauthoridPeng, SM=35464852200en_HK
dc.identifier.scopusauthoridMak, TCW=7401931058en_HK
dc.identifier.scopusauthoridChe, CM=7102442791en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats