Bis(cyclopentadienyl)cobalt

• CAS: 1277-43-6
• Catalog Number: ACM1277436
• Category: Micro/NanoElectronics
• Molecular Weight: 189.12
• Molecular Formula: C₁₀H₁₀Co 1₀*
• Synonyms: bis-(eta5-Cyclopentadienyl) cobalt;Cobalt, bis(eta5-cyclopentadienyl)-;Cobalt, bis(eta5-2,4-cyclopentadien-1-yl)-;Cobalt, di-pi-cyclopentadienyl-;cobalt,bis(η5-2,4-cyclopentadien-1-yl)-;Dicyclopentadienylcobalt;di-pi-cyclopentadienyl-cobal;Kobaltocen
• IUPAC Name: cobalt(2+); cyclopenta-1,3-diene
• InChI Key: ILZSSCVGGYJLOG-UHFFFAOYSA-N
• Boiling Point: 41.5ºC at 760 mmHg
• Melting Point: 176-180ºC (dec.)(lit.)
• Appearance: dark violet crystals
• Exact Mass: 189.01100
• Hazard Statements: F
• H-Bond Acceptor: 2
• H-Bond Donor: 0
• Packing Group: II
• Safety Description: S16-S33
• Stability: Stable, but very reactive and air and moisture sensitive - store under inert gas. Incompatible with strong oxidizing agents. Highly flammable.
• WGK Germany: 3

Case Study

Application of Bis(cyclopentadienyl)cobalt in the Development of n-Type Thermoelectric Composites

Fukumaru, Takahiro, et al. Scientific reports 5.1 (2015): 7951.

This study examined the application of bis(cyclopentadienyl)cobalt (CoCp2 or cobaltocene) as an n-type molecular dopant within single-walled carbon nanotubes (SWNTs) for thermoelectric energy conversion. A practical thermoelectric device was fabricated by combining the n-type CoCp2@SWNT film with a p-type empty SWNT film.
Preparation Strategy: Cobaltocene (CoCp2) was encapsulated inside HiPco single-walled carbon nanotubes using an established filling procedure. The resulting CoCp2@SWNT material was processed into films by dispersing the filled SWNTs in N-methylpyrrolidone (NMP), sonicating, filtering through a 200-nm PTFE membrane, washing and drying. The encapsulated organometallic dopant donates electrons to the SWNT host while being physically confined inside the tube, producing stable n-type transport properties without surface-sensitive dopants that can degrade in air.
Performance: The prepared CoCp2@SWNT film shows a negative Seebeck coefficient (-41.8 μV/K at 320 K), very high electrical conductivity (43,200 S/m at 320 K), a large power factor (75.4 Μw/m/K2) and low thermal conductivity (0.15 W/m/K), giving a ZT of 0.157 at 320 K-the highest reported among n-type organic thermoelectric films in the cited study. The encapsulation strategy yields robust, flexible films that remain stable in air and can be integrated into p-n thermoelectric devices without protective coatings.

Bis(cyclopentadienyl)cobalt as an Anolyte in a Non-Aqueous Redox Flow Battery

Ding, Yu, et al. Energy & Environmental Science 10.2 (2017): 491-497.

Bis(cyclopentadienyl)cobalt (CoCp2 or cobaltocene) was employed as the anode-active species (anolyte) in a prototype lithium-based RFB. It was paired with ferrocene (FeCp2) as the cathode-active species. In this configuration, the cobaltocene undergoes reversible redox reactions at the negative electrode. The system operates as a full "all-metallocene" battery, where the working potential is determined by the difference between the redox potentials of the two organometallic compounds.
Key Performance:
· The reaction rate constants for the metallocenes were measured to be as high as 10^-3 cm/s, significantly exceeding those of many conventional RFB materials. The CoCp2/FeCp2 couple provided a cell working potential of approximately 1.7 V.
· Molecular engineering of the cobaltocene, specifically through the introduction of methyl groups onto its cyclopentadienyl rings, successfully increased the full cell's operating potential by 0.5 V, achieving a discharge potential of up to 2.1 V. The fabricated full cell exhibited excellent stability with capacity retention exceeding 99% per cycle, coupled with a coulombic efficiency of >95% and an energy efficiency of >85%.