Browse history interactively

Page 1

Page 1Revision 1

Page 2

Page 2Revision 2

← Previous editContent deleted Content addedVisualWikitext

Revision as of 14:17, 14 June 2011 editTassedethe (talk | contribs)Autopatrolled, Administrators1,370,825 editsm WPCleaner (v1.08) Repairing link to disambiguation page - (You can help) - Arthur Birch← Previous edit		Latest revision as of 21:25, 19 August 2024 edit undo91.94.70.236 (talk)No edit summaryTags: Mobile edit Mobile web edit
(144 intermediate revisions by 80 users not shown)
Line 1:		Line 1:
			{{short description|Chemical compound}}
			{{Use dmy dates|date=June 2023}}
	{{chembox		{{chembox
			| Verifiedfields = changed
⚫	| verifiedrevid = 401247156
			| Watchedfields = changed
		⚫	| verifiedrevid = 434240157
	| ImageFile = Wilkinson's-catalyst-2D.png		| ImageFile = Wilkinson's-catalyst-2D.png
	| ImageSize = 200px		| ImageSize =
	| ImageName = Wilkinson's catalyst		| ImageName = Wilkinson's catalyst
	| ImageFile1 = Wilkinson's-catalyst-no-hydrogens-3D-balls.png		| ImageFile1 = Wilkinson's-catalyst-no-hydrogens-3D-balls.png
Line 11:		Line 15:
	| ImageName2 = Wilkinson's catalyst		| ImageName2 = Wilkinson's catalyst
	| ImageFile3 = Wilkinson's Cataylst-powder2.jpg		| ImageFile3 = Wilkinson's Cataylst-powder2.jpg
	| ImageSize3 = 200px		| ImageSize3 =
	| ImageName3 = Wilkinson's Catalyst		| ImageName3 = Wilkinson's
	| IUPACName = (''SP''-4)chloridotris(triphenylphosphane)<br />rhodium		| IUPACName = (''SP''-4)-chlorido&shy;tris(triphenylphosphene)&shy;rhodium
	| OtherNames = Rhodium(I) tris-<br />(triphenylphosphine) chloride,<br />Wilkinson’s catalyst,<br />Tris(triphenylphosphine)-<br />rhodium chloride		| OtherNames = Rhodium(I) tris(triphenylphosphene) chloride,<br />Wilkinson's catalyst,<br />Tris(triphenylphosphene)&shy;rhodium(I) chloride
	| Section1 = {{Chembox Identifiers		|Section1={{Chembox Identifiers
	| SMILES =
	| EINECS = 238-744-5		| EINECS = 238-744-5
			| CASNo_Ref = {{cascite|correct|CAS}}
	| CASNo = 14694-95-2		| CASNo = 14694-95-2
			| UNII_Ref = {{fdacite|correct|FDA}}
			| UNII = 0FV534BKEV
			| PubChem = 84599
	| RTECS = none		| RTECS = none
			| StdInChI=1S/3C18H15P.ClH.Rh/c3*1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18;;/h3*1-15H;1H;/p-1
			| StdInChIKey = QBERHIJABFXGRZ-UHFFFAOYSA-M
			| SMILES = Cl((c0ccccc0)(c0ccccc0)c0ccccc0)((c0ccccc0)(c0ccccc0)c0ccccc0)(c0ccccc0)(c0ccccc0)c0ccccc0
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
	| Formula = C<sub>54</sub>H<sub>45</sub>ClP<sub>3</sub>Rh		| Formula = C<sub>54</sub>H<sub>45</sub>ClP<sub>3</sub>Rh
	| MolarMass = 925.22 g/mol		| MolarMass = 925.22 g/mol
Line 28:		Line 38:
	| Solubility = insoluble in water		| Solubility = insoluble in water
	| Solvent = other solvents		| Solvent = other solvents
	| SolubleOther = ]		| SolubleOther = 20 g/L (CHCl<sub>3</sub>, CH<sub>2</sub>Cl<sub>2</sub>), 2 g/L (], ])<ref name=IS/>
	| MeltingPt = 245-250 °C		| MeltingPtC = 245 to 250
			| MeltingPt_notes =
	| BoilingPt =		| BoilingPt =
	}}		}}
	| Section3 = {{Chembox Structure		|Section3={{Chembox Structure
	| Coordination = square planar		| Coordination = square planar ''d''<sup>8</sup> (diamagnetic; ''sp''<sup>2</sup>''d''-hybridized)
	| CrystalStruct =		| CrystalStruct =
	| Dipole =		| Dipole =
	}}		}}
	| Section7 = {{Chembox Hazards		|Section7={{Chembox Hazards
	| ExternalMSDS =		| ExternalSDS =
	| MainHazards = none		| MainHazards = none
			| Hazards_ref=<ref>{{cite web |title=Chlorotris(triphenylphosphine)rhodium(I) |url=https://pubchem.ncbi.nlm.nih.gov/compound/84599#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref>
	| RPhrases = none
	| SPhrases = {{S22}} {{S24/25}}		| GHSPictograms = {{GHS07}}
			| GHSSignalWord = Warning
			| HPhrases = {{H-phrases|302|317|413}}
			| PPhrases = {{P-phrases|261|264|270|272|273|280|301+312|302+352|330|333+313|363|501}}
	}}		}}
	| Section8 = {{Chembox Related		|Section8={{Chembox Related
	| OtherCpds = ]<br />]<br /><sub>2</sub>]]		| OtherCompounds = ]<br />]<br /><sub>2</sub>]]
	}}		}}
	}}		}}
	'''Wilkinson's catalyst''' is the common name for '''chlorotris(triphenylphosphine)rhodium(I)''', a ] with the formula RhCl(PPh<sub>3</sub>)<sub>3</sub> (Ph = phenyl). It is named after the late ] chemist and 1973 Nobel Laureate, Sir ] who popularized its use.		'''Wilkinson's catalyst''' ('''chlorido&shy;tris(triphenylphosphine)&shy;rhodium(I)''') is a ] of ] with the formula , where 'Ph' denotes a ]. It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in ] or chlorinated solvents such as ]. The compound is widely used as a catalyst for hydrogenation of ]s. It is named after chemist and Nobel laureate Sir ], who first popularized its use.
			Historically, Wilkinson's catalyst has been a paradigm in catalytic studies leading to several advances in the field such as the implementation of some of the first heteronuclear magnetic resonance studies for its structural elucidation in solution (<sup>31</sup>P),<ref>{{Cite journal|last1=Meakin|first1=P.|last2=Jesson|first2=J. P.|last3=Tolman|first3=C. A.|date=1 May 1972|title=Nature of chlorotris(triphenylphosphene)rhodium in solution and its reaction with hydrogen|journal=Journal of the American Chemical Society|volume=94|issue=9|pages=3240–3242|doi=10.1021/ja00764a061|issn=0002-7863}}</ref> ] to determine the nature of transient reactive species,<ref>{{Cite journal|last1=Duckett|first1=Simon B.|last2=Newell|first2=Connie L.|last3=Eisenberg|first3=Richard|title=Observation of New Intermediates in Hydrogenation Catalyzed by Wilkinson's Catalyst, RhCl(PPh3)3, Using Parahydrogen-Induced Polarization|journal=Journal of the American Chemical Society|volume=116|issue=23|pages=10548–10556|doi=10.1021/ja00102a023|year=1994}}</ref> or one of the first detailed kinetic investigation by Halpern to elucidate the mechanism.<ref>{{Cite journal|last=Halpern|first=Jack|date=1 January 1981|title=Mechanistic aspects of homogeneous catalytic hydrogenation and related processes|journal=Inorganica Chimica Acta|volume=50|pages=11–19|doi=10.1016/S0020-1693(00)83716-0}}</ref> Furthermore, the catalytic and organometallic studies on Wilkinson's catalyst also played a significant role on the subsequent development of cationic Rh- and Ru-based asymmetric hydrogenation transfer catalysts which set the foundations for modern asymmetric catalysis.<ref>{{Cite book|title=Organotransition metal chemistry- From bonding to Catalysis|last=Hartwig|first=John F.|publisher=University Science Books|year=2010|isbn=978-1-891389-53-5}}</ref>
	==Structure and basic properties==		==Structure and basic properties==
			According to single crystal X-ray diffraction the compound adopts a slightly distorted square planar structure.<ref>{{cite journal | last1 = Bennett | first1 = Michael J. | last2 = Donaldson | first2 = Peter B. | year = 1977 | title = Crystal and molecular structure of the orange and red allotropes of chlorotris(triphenylphosphine)rhodium(I) | journal = Inorganic Chemistry | volume = 16 | issue = 3| pages = 655–660 | doi = 10.1021/ic50169a033}}</ref>
	The compound is a square planar, 16-electron complex. It is usually obtained in the form of a red-violet crystalline solid from the reaction of ] with excess ]. The synthesis is conducted in refluxing ethanol.<ref>{{cite journal|author=Osborn, J. A.; Jardine, F. H.; Young, J. F.; Wilkinson, G.| title=The Preparation and Properties of Tris(triphenylphosphine)halogenorhodium(I) and Some Reactions Thereof Including Catalytic Homogeneous Hydrogenation of Olefins and Acetylenes and Their Derivatives| journal= ] | date = 1966 | pages = 1711–1732 | doi = 10.1039/J19660001711}}</ref> ] serves as the reducing agent yielding ].
⚫	:RhCl<sub>3</sub>(H<sub>2</sub>O)<sub>3</sub> + 4 PPh<sub>3</sub> &rarr; RhCl(PPh<sub>3</sub>)<sub>3</sub> + O=PPh<sub>3</sub> + 2 HCl + 2 H<sub>2</sub>O
			In analyzing the bonding, it is a complex of Rh(I), a ''d''<sup>8</sup> ] ion. From the perspective of the ], the four ligands each provides two electrons, for a total of 16-electrons. As such the compound is ], i.e. susceptible to binding substrates (alkenes and H<sub>2</sub>). In contrast, IrCl(PPh<sub>3</sub>)<sub>3</sub> undergoes cyclometallation to give HIrCl(PPh<sub>3</sub>)<sub>2</sub>(PPh<sub>2</sub>C<sub>6</sub>H<sub>4</sub>), a coordinatively saturated Ir(III) complex that is not catalytically active.<ref>{{cite journal|doi=10.1021/ja01053a016|title=Chlorotris(triphenylphosphine)iridium(I) and Related Complexes. Oxidative Addition Reactions and Hydrogen Abstraction from the Coordinated Ligand|journal=Journal of the American Chemical Society|volume=91|issue=25|pages=6983–6994|year=1969|last1=Bennett|first1=M. A.|last2=Milner|first2=D. L.}}</ref>
			== Synthesis ==
			Wilkinson's catalyst is usually obtained by treating ] with an excess of ] in refluxing ethanol.<ref name="Bennett">{{cite journal|last1=Bennett|first1= M. A.|last2= Longstaff|first2= P. A.|title= Complexes of Rhodium(I) with Triphenylphosphine. |journal=Chem. Ind. (London) |date=1965|volume=1965 |page=846}}</ref><ref name="Osborn">{{cite journal|last1=Osborn |first1=J. A. |last2=Jardine|first2=F. H. |last3=Young |first3=J. F. |author4=Geoffrey Wilkinson | title=The Preparation and Properties of Tris(triphenylphosphine)halogenorhodium(I) and Some Reactions Thereof Including Catalytic Homogeneous Hydrogenation of Olefins and Acetylenes and Their Derivatives| journal= ] | year = 1966|volume=1966 | pages = 1711–1732 | doi = 10.1039/J19660001711|author4-link=Geoffrey Wilkinson }}</ref><ref name=IS>{{cite book|chapter=Tris(triphenylphosphine)halorhodium(I) |first1= J. A. |last1=Osborn |first2=G. |last2=Wilkinson |title= Inorganic Syntheses |year= 1967 |volume=10 |page=67|doi=10.1002/9780470132418.ch12|isbn= 9780470132418 }}</ref> Triphenylphosphine serves as both a ] and a two-electron reducing agent that oxidizes itself from oxidation state (III) to (V). In the synthesis, three equivalents of triphenylphosphine become ligands in the product, while the fourth reduces rhodium(III) to rhodium(I).
		⚫	:RhCl<sub>3</sub>(H<sub>2</sub>O)<sub>3</sub> + 4 PPh<sub>3</sub> → RhCl(PPh<sub>3</sub>)<sub>3</sub> + OPPh<sub>3</sub> + 2 HCl + 2 H<sub>2</sub>O
	==Catalytic applications==		==Catalytic applications==
	Wilkinson's catalyst ] the ] of alkenes.<ref>{{cite journal | author = ], D. H. Williamson | journal = ] | year = 1976 | volume = 24 | pages = 1ff}}</ref><ref>B.R. James, ''Homogeneous Hydrogenation''. John Wiley & Sons, New York, 1973.</ref> The mechanism of this reaction involves the initial dissociation of one or two triphenylphosphine ligands to give 14- or 12-electron complexes, respectively, followed by ] of H<sub>2</sub> to the metal. Subsequent π-complexation of alkene, intramolecular hydride transfer (olefin insertion), and ] results in extrusion of the alkane product, ''e.g.'':		Wilkinson's catalyst is best known for ] the ] of olefins with molecular hydrogen.<ref>{{cite journal | author1 = Arthur Birch |first2= D. H. |last2=Williamson | journal = ] | year = 1976 | volume = 24 | pages = 1 |title = Homogeneous Hydrogenation Catalysts in Organic Synthesis|author1-link= Arthur Birch (organic chemist) }}</ref><ref>{{cite book|first=B. R.|last= James |title=Homogeneous Hydrogenation |publisher=John Wiley & Sons |location=New York, NY|date=1973}}</ref> The mechanism of this reaction involves the initial dissociation of one or two triphenylphosphine ligands to give 14- or 12-electron complexes, respectively, followed by ] of H<sub>2</sub> to the metal. Subsequent π-complexation of alkene, migratory insertion (intramolecular hydride transfer or olefin insertion), and ] complete the formation of the ] product, e.g.:<ref>{{cite web|url=https://www.ch.imperial.ac.uk/rzepa/blog/?p=26709|first=Henry|last=Rzepa|author-link=Henry Rzepa|website=Chemistry with a Twist|title=A mechanistic exploration of the Wilkinson hydrogenation catalyst. Part 1: Model templates|date=21 Jan 2024}}</ref>
			]
			In terms of their rates of hydrogenation, the degree of substitution on the olefin substrate is the key factor, since the rate-limiting step in the mechanism is the insertion into the olefin which is limited by the severe steric hindrance around the metal center. In practice, terminal and disubstituted alkenes are good substrates, but more hindered alkenes are slower to hydrogenate. The hydrogenation of alkynes is troublesome to control since alkynes tend to be reduced to alkanes, via intermediacy of the cis-alkene.<ref name=Burgess>Kevin Burgess, ], Chul-Ho Jun, Young Jun Park, "Chlorotris(triphenylphosphine)-rhodium(I)" Encyclopedia of Reagents for Organic Synthesis 2005 John Wiley & Sons. {{doi|10.1002/047084289X.rc162s.pub2}}</ref> Ethylene reacts with Wilkinson's catalyst to give RhCl(C<sub>2</sub>H<sub>4</sub>)(PPh<sub>3</sub>)<sub>2</sub>, but it is not a substrate for hydrogenation.<ref name=Osborn/>
	<center>]</center>
			===Related catalytic processes===
	Other applications of Wilkinson’s catalyst includes the catalytic ] of alkenes with catecholborane and ],<ref>{{cite journal | author = D. A. Evans, G. C. Fu and A. H. Hoveyda | title = Rhodium(I)-catalyzed hydroboration of olefins. The documentation of regio- and stereochemical control in cyclic and acyclic systems | year = 1988 | journal = ] | volume = 110 | issue = 20 | pages = 6917–6918 | doi=10.1021/ja00228a068}}</ref> and the selective ] of α, β-unsaturated ] compounds in concert with ].<ref>{{cite journal | author = I. Ojima, T. Kogure | journal = ] | year = 1972 | volume = 13 | issue = 49 | pages = 5035–5038 | doi = 10.1016/S0040-4039(01)85162-5 | title = Selective reduction of α,β-unsaturated terpene carbonyl compounds using hydrosilane-rhodium(I) complex combinations}}</ref> When the triphenylphosphine ligands are replaced by ]		Wilkinson's catalyst also catalyzes many other hydrofunctionalization reactions including ], ], and ] of alkenes.<ref name=Burgess/> Hydroborations have been studied with ] and ].<ref>{{cite journal | first1 = D. A. |last1=Evans |first2=G. C. |last2=Fu |first3=A. H. |last3=Hoveyda | title = Rhodium(I)-catalyzed hydroboration of olefins. The documentation of regio- and stereochemical control in cyclic and acyclic systems | year = 1988 | journal = ] | volume = 110 | issue = 20 | pages = 6917–6918 | doi=10.1021/ja00228a068}}</ref> It is also active for the hydrosilylation of alkenes.<ref>{{cite journal | first1 = I. |last1=Ojima |first2=T. |last2=Kogure | journal = ] | year = 1972 | volume = 13 | issue = 49 | pages = 5035–5038 | doi = 10.1016/S0040-4039(01)85162-5 | title = Selective reduction of α,β-unsaturated terpene carbonyl compounds using hydrosilane-rhodium(I) complex combinations}}</ref>
	phosphines (e.g., ], ], DIOP), the catalyst becomes chiral and converts ] alkenes into enantiomerically enriched alkanes via the process called asymmetric hydrogenation.<ref>{{cite journal | author = ] | title = Asymmetric Hydrogenations (Nobel Lecture 2001) | journal = ] | year = 2003 | volume = 345 | issue = 12 | pages = 3–13 | doi = 10.1002/adsc.200390028 }}</ref>
			In the presence of strong base and hydrogen, Wilkinson's catalyst forms reactive Rh(I) species with superior catalytic activities on the hydrogenation of internal alkynes and functionalized tri-substituted alkenes.<ref>{{Cite journal|last1=Perea Buceta|first1=Jesus E.|last2=Fernández|first2=Israel|last3=Heikkinen|first3=Sami|last4=Axenov|first4=Kirill|last5=King|first5=Alistair W. T.|last6=Niemi|first6=Teemu|last7=Nieger|first7=Martin|last8=Leskelä|first8=Markku|last9=Repo|first9=Timo|date=23 November 2015|orig-year=2015|title=Diverting Hydrogenations with Wilkinson's Catalyst towards Highly Reactive Rhodium(I) Species|journal=Angewandte Chemie International Edition|language=en|volume=54|issue=48|pages=14321–14325|doi=10.1002/anie.201506216|pmid=26437764|issn=1521-3773}}</ref>
	==Other reactions of RhCl(PPh<sub>3</sub>)<sub>3</sub>==
⚫	RhCl(PPh<sub>3</sub>)<sub>3</sub> reacts with CO to give trans-RhCl(CO)(PPh<sub>3</sub>)<sub>2</sub>, which is structurally analogous to ] (but much less reactive). The same complex arises from the decarbonylation of ]s:
			==Reactions==
		⚫	RhCl(PPh<sub>3</sub>)<sub>3</sub> reacts with ] to give ], ''trans''-RhCl(CO)(PPh<sub>3</sub>)<sub>2</sub>. The same complex arises from the decarbonylation of ]s:
	:RhCl(PPh<sub>3</sub>)<sub>3</sub> + RCHO → RhCl(CO)(PPh<sub>3</sub>)<sub>2</sub> + RH + PPh<sub>3</sub>		:RhCl(PPh<sub>3</sub>)<sub>3</sub> + RCHO → RhCl(CO)(PPh<sub>3</sub>)<sub>2</sub> + RH + PPh<sub>3</sub>
	Upon stirring in benzene solution, RhCl(PPh<sub>3</sub>)<sub>3</sub> converts to the poorly soluble red-colored species Rh<sub>2</sub>Cl<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>. This conversion further demonstrates the lability of the triphenylphosphine ligands.		Upon stirring in benzene solution, RhCl(PPh<sub>3</sub>)<sub>3</sub> converts to the poorly soluble red-colored ] <sub>2</sub>. This conversion further demonstrates the lability of the triphenylphosphine ligands.
			In the presence of base, H<sub>2</sub>, and additional triphenylphosphine, Wilkinson's complex converts to ], HRh(PPh<sub>3</sub>)<sub>4</sub>. This 18e complex is also an active hydrogenation catalyst.<ref>Eduardo Peña-Cabrera "Hydridotetrakis(triphenylphosphine)rhodium" Encyclopedia of Reagents for Organic Synthesis, 2001, John Wiley & Sons. {{doi|10.1002/047084289X.rh030m}}</ref>
			==See also==
			*]
	==References==		==References==
	{{reflist}}		{{reflist|30em}}
	]		{{Rhodium compounds}}
			]
	]		]
	]		]
	]		]
	]		]
			]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]