Methylcyclopentadienyl manganese tricarbonyl
General
Systematic name	(Methylcyclopentadienyl)- manganese(I) tricarbonyl
Other names	MMT
Molecular formula	C9H8MnO3
SMILES	?
Molar mass	218.09 g/mol
Appearance	pale yellow liquid herbaceous odor
CAS number	[12108-13-3]
Properties
Density and phase	? g/cm3
Solubility in water	low
Other solvents	alkane (petrol)
Melting point	-1 °C (? K)
Boiling point	232-233 °C
Viscosity	? cP at ? °C
Structure
Coordination geometry	Tetrahedral at Mn
Crystal structure	?
Dipole moment	? D
Hazards
MSDS	External MSDS
Main hazards	flammable
NFPA 704
Flash point	205 °F
R/S statement	R: 23/24/25-40 S: 23-26-36/37/39-45
RTECS number	OP1450000
Supplementary data page
Structure and properties	n 1.584
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related compounds	ferrocene Mn2(CO)10 dicyclopentadiene
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organometallic compound with the formula (CH₃C₅H₄)Mn(CO)₃. Marketed initially in 1958 as a supplement to the gasoline additive, tetraethyl lead to increase the fuels octane rating, MMT was later used in unleaded gasoline.^[1] Although banned as a gasoline additive in the United States from 1977 to 1995, MMT has been used in Canadian gasoline since 1976 and was recently introduced in Australia. It is sold under the tradenames HiTec 3000 and AK-33X.^[2] Image File history File links Size of this preview: 713 × 600 pixel Image in higher resolution (1100 × 925 pixel, file size: 53 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Methylcyclopentadienyl manganese tricarbonyl... 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NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for labeling dangerous chemicals and compounds. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... IR spectrum of a thin film of liquid ethanol. ... Nuclear Magnetic Resonance Spectroscopy most commonly known as NMR Spectroscopy is the name given to the technique which exploits the magnetic properties of nuclei. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or in common speech mass-spec) is an analytical technique used to measure the mass-to-charge ratio of ions. ... Ferrocene is the chemical compound with the formula Fe(C5H5)2. ... Dimanganese decacarbonyl is the chemical compound Mn2(CO)10. ... Dicyclopentadiene, C10H12, is a hydrocarbon found in oil deposits. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... An organometallic compound is partially characterized by the presence of one or more metal-carbon bonds, in which the carbon involved would, apart from the metal-carbon bond, be otherwise considered a part of an organic compound. ... It is the intention that Gasoline additives increase the fuels octane rating or act as corrosion inhibitors or lubricators, thus allowing the use of higher compression ratios for greater efficiency and power, however some carry heavy environmental risks. ... Tetra-ethyl lead (also known as TEL, lead tetraethyl and tetraethyllead) is a toxic organometallic chemical compound, with formula (CH2CH3)4Pb, which was once used as a gasoline (petrol) additive. ... A gas station pump offering five different octane ratings. ...

History

Tetraethyl lead (TEL) has been, and still is, used as an additive to increase the octane rating of petrol. TEL was manufactured and marketed by the Ethyl Corporation, a joint venture between General Motors and DuPont. When the US Environmental Protection Agency (EPA) ordered the phase out of leaded petrol in 1972, new fuel additives were sought. Initially marketed in 1958 as a smoke suppressant for gas turbines, MMT was used in 1974 as an additive in unleaded petrol. Ethyl Corporation is responsible for producing TEL(tetraethyl lead) used in cars to prevent engine knock. ... General Motors Corporation, also known as GM, is the worlds largest car manufacturer. ... This article is about the DuPont company. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ...

In 1977, use of MMT was banned in the US by the Clean Air Act until the Ethyl Corporation could prove that the additive would not lead to failure of new car emissions-control systems. As a result of this ruling, the Ethyl Corporation began a legal battle with the EPA, presenting evidence that MMT was harmless to automobile emissions-control systems. In 1995, the U.S. Court of Appeals ruled that the EPA had exceeded its authority and, as a result, MMT became a legal fuel additive in the US.^[3] MMT is nowadays manufactured by the Afton Chemical Corporation division of Newmarket Corporation.^[1]

Structure and bonding

The compound is called a half-sandwich compound. The manganese atom in MMT is bonded to three carbonyl groups as well as to the methylcyclopentadienyl ring. These hydrophobic organic ligands make MMT highly lipophilic, which may be relevant to bioacculumation. A variety of related complexes are known, including ferrocene, which is also under consideration as an additive to petrol. Space-filling model of ferrocene, the archetypal sandwich compound A sandwich compound in organometallic chemistry is any chemical compound containing a metal atom sandwiched between two arene units. ... --141. ... Ferrocene is the chemical compound with the formula Fe(C5H5)2. ...

Preparation

^[4] Image File history File links No higher resolution available. ...

Safety

The health hazards associated with MMT have been hotly debated for decades. A 2003 study by the NICNAS in Australia suggested that MMT was highly toxic to humans in raw concentrated form, but ruled that the airborne concentrations of manganese as a result of car emissions from vehicles using fuel containing MMT posed no health hazard.^[5] A 2002 study by Masashi Kitazawa argued that dermal absorption from accidental gasoline spills, misuse of gasoline as a solvent cleaner, and deliberate gasoline fume inhalation were the main sources of potential MMT exposure. A soda bottle after being filled with blue paint for the means of solvent abuse in Townsville, Australia. ...

Chronic exposure to manganese has been known to cause manganism. The symptoms of manganism are similar to those of Parkinson's disease. MMT has been shown to be cytotoxic and especially damaging to dopaminergic PC-12 cells.^[3] Toxicokinetic studies have shown that manganese derived from MMT absorbs into rat blood plasma at a rate 37 times that of inorganic manganese.^[6] Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese and first identified in 1837 by J. Couper. ... Cytotoxicity is the quality of being poisonous to cells. ... Toxicokinetics is the application of pharmacokinetics to determine the relationship between the systemic exposure of a compound in experimental animals and its toxicity. ...

Immediate symptoms of MMT exposure are mild skin and eye irritation. Short-term symptoms resulting from MMT poisoning include giddiness, headache, neausea, and difficulties in breathing. Animal studies have shown that long-term exposure to MMT can result in damage to the liver and kidneys.^[7]

References

1. ^ ^{a b} http://www.aftonchemical.com/Products/MMT/History+of+MMT®.htm
2. ^ Frumkin, Howard and Solomon, Gena; "Manganese in the US Gas Supply" American Journal of Industrial Medicine, 31: 107-115 (1997)
3. ^ ^{a b} Masashi Kitazawa, Jarrad R. Wagner, Michael L. Kirby, Vellareddy Anantharam, and Anumantha G. Kanthasamy; Oxidative Stress and Mitochondrial-Mediated Apoptosis in Dopaminergic Cells Exposed to Methylcyclopentadienyl Manganese Tricarbonyl J. Pharmacol. Exp. Ther., Jul 2002; 302: 26 - 35.
4. ^ U.S. Patent 4,946,975 
5. ^ National Industrial Chemicals Notification and Assessment Scheme; Methylcyclopentadienyl Manganese Tricarbonyl June 2003. [1]
6. ^ Zheng W, Kim H and Zhao Q (2000) Comparative toxicokinetics of manganese chloride and methylcyclopentadienyl manganese tricarbonyl (MMT) in Sprague-Dawley rats. Toxicol Sci 54: 295-301.
7. ^ United Nations Environment Programme with World Health Organization; Manganese; Geneva, 1981.

External links

• Links to external chemical sources