Methylcyclopentadiene

{{#if:86|! style="background: #F8EABA; text-align: center;" colspan="2" | Properties

Methylcyclopentadiene
File:Methylcyclopentadiene.png
Identifiers
PubChem	66775
ChemSpider	60141 7pxY
Jmol-3D images	Image 1
SMILES C\1=C\C=C(\C)C/1 <p><p style="word-wrap: break-word;">
InChI InChI=1S/C6H8/c1-6-4-2-3-5-6/h2-4H,5H2,1H3 7pxY Key: NFWSQSCIDYBUOU-UHFFFAOYSA-N 7pxY InChI=1/C6H8/c1-6-4-2-3-5-6/h2-4H,5H2,1H3 Key: NFWSQSCIDYBUOU-UHFFFAOYAV
Molecular formula	C6H8
Molar mass	80.13 g mol−1
14pxY (verify) (what is: 10pxY/10pxN?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Methylcyclopentadiene describes three isomeric cyclic diolefins with the formula C₅MeH₅ (Me = CH₃). These isomers are the organic precursor to the methylcyclopentadienyl-ligand (C₅H₄Me, often denoted as Cp'), commonly found in organometallic chemistry. C₅MeH₅ is prepared by thermal cracking its Diels-Alder dimer, followed by distillation to remove cyclopentadiene C₅H₆, a common impurity.

Relative to the corresponding Cp complexes, complexes of Cp' exhibit enhanced solubility in organic solvents. Furthermore Cp' is often employed to probe the structure of organometallic complexes. For example, (MeC₅H₄)Fe(PPh₃)(CO)I, exhibits four MeC₅H₄ resonances in its ¹H NMR spectrum and five MeC₅H₄ resonances in the ¹³C NMR spectrum. Free rotation of the Cp' ligand does not equivalence the diastereopic protons and carbon centers. The achiral precursor complex (MeC₅H₄)Fe(CO)₂)I exhibits only two MeC₅H₄ resonances in the ¹H NMR spectrum and three MeC₅H₄ resonances in the ¹³C NMR spectrum.

File:Cp'FeP(CO)I.png

Structure of (MeC₅H₄)Fe(PPh₃)(CO)I, with labels for the four diastereotopic ring protons.

See also

• Cyclopentadiene
• Pentamethylcyclopentadiene