| 词条 | Cyclopentadienylcobalt dicarbonyl |
| 释义 |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 445343725 | ImageFile1 = Cpco(CO)2.png | Name = Cyclopentadienyl cobalt dicarbonyl | ImageFile2 = Cyclopentadienylcobalt-dicarbonyl-from-xtal-1992-CM-3D-balls.png |Section1={{Chembox Identifiers | CASNo = 12078-25-0 | CASNo_Ref = {{cascite|changed|CAS}} | PubChem = 11986239 | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 10158732 | SMILES = [C-]#[O+].[C-]#[O+].[cH-]1cccc1.[Co] | InChI = 1/C5H5.2CO.Co/c1-2-4-5-3-1;2*1-2;/h1-5H;;;/q-1;;; | InChIKey = AEVRNKXPLOTCBW-UHFFFAOYAD | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 1S/C5H5.2CO.Co/c1-2-4-5-3-1;2*1-2;/h1-5H;;;/q-1;;; | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = AEVRNKXPLOTCBW-UHFFFAOYSA-N |Section2={{Chembox Properties | Formula = CpCo(CO)2 | MolarMass = 180.05 g/mol | Appearance = Dark red to black liquid | Density = 1.35 g/cm3 | MeltingPtC = -22 | BoilingPtC = 139 to 140 | BoilingPt_notes = (710 mmHg) 37-38.5 °C (2 mmHg) | Solubility = Insoluble |Section3={{Chembox Hazards | ExternalSDS = | FlashPtC = 26.7 | RPhrases = {{R10}} {{R23/24/25}} {{R42/43}} {{R53}} | SPhrases = {{S23}} {{S36/37}} {{S45}} }}Cyclopentadienylcobalt dicarbonyl is an organocobalt compound with formula (C5H5)Co(CO)2, abbreviated CpCo(CO)2. It is an example of a half-sandwich complex. It is a dark red air sensitive liquid. This compound features one cyclopentadienyl ring that is bound in an η5-manner and two carbonyl ligands. The compound is soluble in common organic solvents and it is best stored under nitrogen.[1] PreparationCpCo(CO)2 was first reported in 1954 by Piper, Cotton, and Wilkinson who produced it by the reaction of cobalt carbonyl with cyclopentadiene.[2] It is prepared commercially by the same method: Co2(CO)8 + 2 C5H6 → 2 C5H5Co(CO)2 + H2 + 4 CO Alternatively, it is generated by the high pressure carbonylation of bis(cyclopentadienyl)cobalt (cobaltocene) at elevated temperature and pressures: Co(C5H5)2 + 2 CO → C5H5Co(CO)2 + "C5H5" ReactionsCpCo(CO)2 catalyzes the cyclotrimerization of alkynes.[3][4] The catalytic cycle begins with dissociation of one CO ligand forming bis(alkyne) intermediate.[5] CpCo(CO)2 + 2 R2C2 → CpCo(R2C2)2 + 2 CO This reaction proceeds by formation of metal-alkyne complexes by dissociation of CO. Although monoalkyne complexes CpCo(CO)(R1C2R2) have not been isolated, their analogues, CpCo(PPh3)(R1C2R2) are made by the following reactions:[5] CpCo(CO)2 + PR3 → CO + CpCo(CO)(PR3) CpCoL(PR3) + R2C2 → L + CpCo(PR3)(R2C2) (where L = CO or PR3) CpCo(CO)2 catalyzes the formation of pyridines from a mixture of alkynes and nitriles. Reduction of CpCo(CO)2 with sodium yields the dinuclear radical [Cp2Co2(CO)2]−, which reacts with alkyl halides to give the dialkyl complexes [Cp2Co2(CO)2R2]. Ketones are produced by carbonylation of these dialkyl complexes, regenerating CpCo(CO)2.[5] Related compoundsThe pentamethylcyclopentadienyl analogue Cp*Co(CO)2 (CAS RN#12129-77-0) is well studied. The Rh and Ir analogues, CpRh(CO)2 (CAS RN#12192-97-1) and CpIr(CO)2 (CAS RN#12192-96-0), are also well known. References1. ^{{cite journal | author = King, R.B.; Stone, F.G.A | title = Cyclopentadienyl Metal Carbonyls and Some Derivatives | journal = Inorg. Synth. | volume = 7 | doi = 10.1002/9780470132388.ch31 | year = 1963 | pages = 99}} {{cobalt compounds}}2. ^{{cite journal | author = Piper, T.S.; Cotton, F.A.; Wilkinson, G. | title = Cyclopentadienyl-carbon monoxide and related compounds of some transitional metals. | journal = Journal of Inorganic and Nuclear Chemistry | doi = 10.1016/0022-1902(55)80053-X | year = 1955 | volume = 1 | issue = 3 | pages = 165}} 3. ^{{cite journal|title=Cobalt-assisted [2+2+2] cycloadditions: a synthesis strategy grows to maturity|author= Vollhardt, K. Peter C.|journal=Angewandte Chemie|year=1984|volume=96|pages=525–41|doi=10.1002/ange.19840960804}} 4. ^{{cite journal |author1=Staeb, T.H. |author2=Chavez, J. |author3=Gleiter, R. |author4=Nuber, Bernhard | title = The Role of [η2-Bis(tert-butylsulfonyl)acetylene](carbonyl)(η5-cyclopentadienyl) cobalt(I) as an Intermediate in the Alkyne Dimerisation | journal = Eur. J. Inorg. Chem. | doi = 10.1002/ejic.200500394 | year = 2005 | volume = 2005 | issue = 20 | pages = 4090}} 5. ^1 2 Pauson, P.L. “Dicarbonyl(cyclopentadienyl)cobalt(I).” Encyclopedia of Reagents for Organic Synthesis. 2001. {{DOI|10.1002/047084289X.rd078}} 4 : Cyclopentadienyl complexes|Carbonyl complexes|Organocobalt compounds|Half sandwich compounds |
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