Decamethylcobaltocene is an organocobalt compound with the formula Co(C5(CH3)5)2, abbreviated CoCp∗ 2. It is a dark brown solid. This compound is used as a strong reducing agent in organometallic chemistry.
Decamethylcobaltocene is prepared by treatment of LiCp* with CoCl2:
2 LiCp* + CoCl2 → 2 LiCl + CoCp*2
The permethylated form is more air-sensitive than the parent cobaltocene, owing to the inductive effects of methyl groups. It is a thermally stable compound and undergoes vacuum sublimation.
BondingEdit
Co(C5Me5)2 is a metallocene, having idealized D5d symmetry. Like cobaltocene, decamethylcobaltocene has a 19 electron count in its valence shell and is paramagnetic.
It is used as a one-electron reducing agent. Relative to the ferrocene/ferrocenium couple, the redox potential for the [CoCp*2]+/0 couple is -1.94 V compared to the [CoCp2]+/0 couple of -1.33 V (in dichloromethane). For comparison, the difference between the redox ferrocene and its permethylated derivative FeCp*2+/0 couple is -0.59 V (also in dichloromethane).[1]
StructureEdit
Decamethylcobaltocene and decamethylferrocene have very similar structures.[2] The additional electron occupies an orbital that is anti-bonding with respect to the Co-C bonds. Co-C distances of 2.118 Å at room temperature are slightly longer than seen in other metallocenes such as the Fe-C bonds in ferrocene, and fairly longer than its parent cobaltocene at 2.096 Å at room temperature (in the gas-phase, the Co-C distances in Cp2Co is 2.119 Å, closely resembling the Co-C bond lengths of decamethylcobaltocene.[3]
An illustrative redox reaction of decamethylcobaltocene is:
2 CoCp*2 + C60 → 2 [CoCp*2]+ + [C60]2−
ReferencesEdit
^Connelly, Neil G., Geiger, Willam E. Chemical Redox Agents for Organometallic Chemistry. Chemistry Reviews. 1996. P. 877-910.DOI: 10.1021/cr940053x.
^Clark, Meghan M., Brennessel, William W., Holland, Patrick L. "Bis(η5-pentamethylcyclopentadienyl)cobalt(II)" Acta Crystallographica Structures Online Reports. 2009, Vol.65, . DOI.
^Antipin, Yu M., Augart, N., Boese, R., Schmid, G. Redetermination of the cobaltocene crystal structure at 100K and 297K. Structural Chemistry. Volume 4, No. 2. 1993. P. 91-101.
August 26, 2023
decamethylcobaltocene, organocobalt, compound, with, formula, abbreviated, cocp, dark, brown, solid, this, compound, used, strong, reducing, agent, organometallic, chemistry, namesiupac, name, pentamethylcyclopentadienyl, cobalt, other, names, pentamethylcyclo. Decamethylcobaltocene is an organocobalt compound with the formula Co C5 CH3 5 2 abbreviated CoCp 2 It is a dark brown solid This compound is used as a strong reducing agent in organometallic chemistry Decamethylcobaltocene NamesIUPAC name Bis h5 pentamethylcyclopentadienyl cobalt II Other names bis h5 pentamethylcyclopentadienyl cobaltIdentifiersCAS Number 74507 62 3 Y3D model JSmol Interactive imageChemSpider 4321575 NPubChem CID 5148110CompTox Dashboard EPA DTXSID80996013InChI InChI 1S 2C10H15 Co c2 1 6 7 2 9 4 10 5 8 6 3 h2 1 5H3 q2 1 2 NKey NGJVBICXQZVNEF UHFFFAOYSA N NInChI 1 2C10H15 Co c2 1 6 7 2 9 4 10 5 8 6 3 h2 1 5H3 q2 1 2Key NGJVBICXQZVNEF UHFFFAOYAUSMILES C c 1c c c c1C C C C C c 1c c c c1C C C C Co 2 PropertiesChemical formula C 20H 30CoMolar mass 329 393 g mol 1Appearance dark brownMelting point gt 210 C 410 F 483 K Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Contents 1 Synthesis 2 Bonding 3 Structure 4 ReferencesSynthesis EditDecamethylcobaltocene is prepared by treatment of LiCp with CoCl2 2 LiCp CoCl2 2 LiCl CoCp 2The permethylated form is more air sensitive than the parent cobaltocene owing to the inductive effects of methyl groups It is a thermally stable compound and undergoes vacuum sublimation Bonding EditCo C5Me5 2 is a metallocene having idealized D5d symmetry Like cobaltocene decamethylcobaltocene has a 19 electron count in its valence shell and is paramagnetic It is used as a one electron reducing agent Relative to the ferrocene ferrocenium couple the redox potential for the CoCp 2 0 couple is 1 94 V compared to the CoCp2 0 couple of 1 33 V in dichloromethane For comparison the difference between the redox ferrocene and its permethylated derivative FeCp 2 0 couple is 0 59 V also in dichloromethane 1 Structure EditDecamethylcobaltocene and decamethylferrocene have very similar structures 2 The additional electron occupies an orbital that is anti bonding with respect to the Co C bonds Co C distances of 2 118 A at room temperature are slightly longer than seen in other metallocenes such as the Fe C bonds in ferrocene and fairly longer than its parent cobaltocene at 2 096 A at room temperature in the gas phase the Co C distances in Cp2Co is 2 119 A closely resembling the Co C bond lengths of decamethylcobaltocene 3 An illustrative redox reaction of decamethylcobaltocene is 2 CoCp 2 C60 2 CoCp 2 C60 2 References Edit Connelly Neil G Geiger Willam E Chemical Redox Agents for Organometallic Chemistry Chemistry Reviews 1996 P 877 910 DOI 10 1021 cr940053x Clark Meghan M Brennessel William W Holland Patrick L Bis h5 pentamethylcyclopentadienyl cobalt II Acta Crystallographica Structures Online Reports 2009 Vol 65 DOI Antipin Yu M Augart N Boese R Schmid G Redetermination of the cobaltocene crystal structure at 100K and 297K Structural Chemistry Volume 4 No 2 1993 P 91 101 Retrieved from https en wikipedia org w index php title Decamethylcobaltocene amp oldid 940462391, wikipedia, wiki, book, books, library,
