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Article: Reaction of [Os3(μ-H)2(CO)9(μ3-CNC5H4CH=CH2)] with phenylacetylene: a novel type of alkylidyne-alkyne coupling in trisomium alkylidyne cluster

TitleReaction of [Os3(μ-H)2(CO)9(μ3-CNC5H4CH=CH2)] with phenylacetylene: a novel type of alkylidyne-alkyne coupling in trisomium alkylidyne cluster
Authors
Issue Date1995
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, 1995, n. 9, p. 1497-1509 How to Cite?
AbstractReaction of the alkylidyne cluster [Os3(µ-H)2(CO)9(µ3-CNC5H4CH[double bond, length half m-dash]CH2)]1 with the unsymmetrical alkyne PhC[triple bond, length half m-dash]CH occurred under thermal conditions affording two pairs of geometrical isomers [Os3(µ-H)(CO)9{µ3-η3-PhCCHC(CH[double bond, length half m-dash]CHPh)}]2a(30%), [Os3(CO)9(µ3-η1,η2,η2,η1-PhCHCH[double bond, length half m-dash]CH-CH[double bond, length half m-dash]CPh)]2b(24%), [Os3(CO)7{µ-η2,η3-CH2[double bond, length half m-dash]CHC(Ph)CHCPh}{µ3-η2-C(O)C(Ph)[double bond, length half m-dash]CH}]3a(8%), [Os3(CO)7{µ-η2,η3-PhCH[double bond, length half m-dash]CHC(Ph)CHCH}{µ3-η2-C(O)C(Ph)[double bond, length half m-dash]CH}]3b(6%) and the known cluster [Os3(µ-H)(CO)9{µ-C(H)NC5H4(η2-CH[double bond, length half m-dash]CH2)}]4(7%). The same reaction, carried out at room temperature in acetone, yielded another new cluster [Os3(CO)8(µ-η2-PhCCH2)(µ3-η2-CHCPhCH)]5 as a major product (34%). All the compounds have been fully characterised by spectroscopic and X-ray diffraction methods. The structure of 2a reveals that the methylidyne carbon in the ‘Os3C’ core couples with two phenylacetylene molecules to form a novel C5 hydrocarbyl co-ordinated in an allyl fashion on the trimetallic surface. Cluster 2b, an isomer of 2a, contains a cis,cis-1,5-diphenylpenta-1,3-diene ligand on a triangular array of Os atoms which, together with one of the osmium atoms forms an osmacyclohexa-2,4-diene ring with two localised double bonds. The structures of both 3a and 3b show the coupling of three alkyne molecules with 1, resulting in the formation of two discrete organic fragments. An interesting feature in both compounds is the formation of a keto ligand with a µ3-η2-co-ordination mode, which is derived from the coupling of one carbonyl ligand and a phenylacetylene molecule. The other fragment adopts a µ-η2,η3-co-ordination mode with a π and a η3-allyl bond to give a metallacyclic ring system. The two complexes are isomeric and differ only in the spatial positions of the phenyl substituents in the C5 hydrocarbyl fragments. The structure of 5 contains a σ,π-vinyl group with a µ-η2-bonding mode and an allyl fragment with a µ3-η3-co-ordination mode. A proposed mechanism which involves the cleavage of the N–C(alkylidyne) bond in 1, resulting in the formation of a µ3-carbido species ‘[Os3(µ-H)2(CO)9(µ3-C)]’ or a µ-alkylidene fragment ‘[Os3(µ-H)(CO)9(µ-CH)]’ as the intermediate is put forward to explain the unusual coupling reaction sequence. The reaction of 1 with p-tolylacetylene in refluxing n-hexane was studied to support the suggested mechanism and another two pairs of geometrical isomers were fully characterised with the crystal structure of [Os3(CO)9(µ3-η1,η2,η2,η1-MeC6H4CHCH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CC6H4Me)]6b determined. The basic hydrocarbyl skeleton on the Os3 triangle in 6b is essentially the same as in the analogous compound 2b except for the presence of two methyl groups on the phenyl rings. This precludes the existence of the original pyridine ring in the newly formed clusters.
Persistent Identifierhttp://hdl.handle.net/10722/70418
ISSN
2002 Impact Factor: 3.023
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorChan, Sen_HK
dc.contributor.authorWong, WYen_HK
dc.contributor.authorWong, WTen_HK
dc.date.accessioned2010-09-06T06:22:41Z-
dc.date.available2010-09-06T06:22:41Z-
dc.date.issued1995en_HK
dc.identifier.citationJournal of the Chemical Society Dalton Transactions, 1995, n. 9, p. 1497-1509en_HK
dc.identifier.issn1472-7773en_HK
dc.identifier.urihttp://hdl.handle.net/10722/70418-
dc.description.abstractReaction of the alkylidyne cluster [Os3(µ-H)2(CO)9(µ3-CNC5H4CH[double bond, length half m-dash]CH2)]1 with the unsymmetrical alkyne PhC[triple bond, length half m-dash]CH occurred under thermal conditions affording two pairs of geometrical isomers [Os3(µ-H)(CO)9{µ3-η3-PhCCHC(CH[double bond, length half m-dash]CHPh)}]2a(30%), [Os3(CO)9(µ3-η1,η2,η2,η1-PhCHCH[double bond, length half m-dash]CH-CH[double bond, length half m-dash]CPh)]2b(24%), [Os3(CO)7{µ-η2,η3-CH2[double bond, length half m-dash]CHC(Ph)CHCPh}{µ3-η2-C(O)C(Ph)[double bond, length half m-dash]CH}]3a(8%), [Os3(CO)7{µ-η2,η3-PhCH[double bond, length half m-dash]CHC(Ph)CHCH}{µ3-η2-C(O)C(Ph)[double bond, length half m-dash]CH}]3b(6%) and the known cluster [Os3(µ-H)(CO)9{µ-C(H)NC5H4(η2-CH[double bond, length half m-dash]CH2)}]4(7%). The same reaction, carried out at room temperature in acetone, yielded another new cluster [Os3(CO)8(µ-η2-PhCCH2)(µ3-η2-CHCPhCH)]5 as a major product (34%). All the compounds have been fully characterised by spectroscopic and X-ray diffraction methods. The structure of 2a reveals that the methylidyne carbon in the ‘Os3C’ core couples with two phenylacetylene molecules to form a novel C5 hydrocarbyl co-ordinated in an allyl fashion on the trimetallic surface. Cluster 2b, an isomer of 2a, contains a cis,cis-1,5-diphenylpenta-1,3-diene ligand on a triangular array of Os atoms which, together with one of the osmium atoms forms an osmacyclohexa-2,4-diene ring with two localised double bonds. The structures of both 3a and 3b show the coupling of three alkyne molecules with 1, resulting in the formation of two discrete organic fragments. An interesting feature in both compounds is the formation of a keto ligand with a µ3-η2-co-ordination mode, which is derived from the coupling of one carbonyl ligand and a phenylacetylene molecule. The other fragment adopts a µ-η2,η3-co-ordination mode with a π and a η3-allyl bond to give a metallacyclic ring system. The two complexes are isomeric and differ only in the spatial positions of the phenyl substituents in the C5 hydrocarbyl fragments. The structure of 5 contains a σ,π-vinyl group with a µ-η2-bonding mode and an allyl fragment with a µ3-η3-co-ordination mode. A proposed mechanism which involves the cleavage of the N–C(alkylidyne) bond in 1, resulting in the formation of a µ3-carbido species ‘[Os3(µ-H)2(CO)9(µ3-C)]’ or a µ-alkylidene fragment ‘[Os3(µ-H)(CO)9(µ-CH)]’ as the intermediate is put forward to explain the unusual coupling reaction sequence. The reaction of 1 with p-tolylacetylene in refluxing n-hexane was studied to support the suggested mechanism and another two pairs of geometrical isomers were fully characterised with the crystal structure of [Os3(CO)9(µ3-η1,η2,η2,η1-MeC6H4CHCH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CC6H4Me)]6b determined. The basic hydrocarbyl skeleton on the Os3 triangle in 6b is essentially the same as in the analogous compound 2b except for the presence of two methyl groups on the phenyl rings. This precludes the existence of the original pyridine ring in the newly formed clusters.-
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.titleReaction of [Os3(μ-H)2(CO)9(μ3-CNC5H4CH=CH2)] with phenylacetylene: a novel type of alkylidyne-alkyne coupling in trisomium alkylidyne clusteren_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1472-7773&volume=9&spage=1497&epage=1509&date=1995&atitle=Reaction+of+[Os3(m-H)2(CO)9(m3-CNC5H4-CH=CH2)]+with+phenylacetylene:+a+novel+type+of+alkylidyne-alkyne+coupling+in+trisomium+alkylidyne+clusteren_HK
dc.identifier.emailWong, WT: wtwong@hku.hken_HK
dc.identifier.authorityWong, WT=rp00811en_HK
dc.identifier.doi10.1039/DT9950001497-
dc.identifier.hkuros1489en_HK
dc.identifier.issue9-
dc.identifier.spage1497-
dc.identifier.epage1509-
dc.identifier.isiWOS:A1995QY25400016-

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