Methylcyclopentadiene

Methylcyclopentadiene
Identifiers
3D model (JSmol)	Interactive image;
ChemSpider	60141 ;
ECHA InfoCard	100.043.400
PubChem CID	66775;
	InChI InChI=1S/C6H8/c1-6-4-2-3-5-6/h2-4H,5H2,1H3 Key: NFWSQSCIDYBUOU-UHFFFAOYSA-N ; InChI=1/C6H8/c1-6-4-2-3-5-6/h2-4H,5H2,1H3 Key: NFWSQSCIDYBUOU-UHFFFAOYAV;
	SMILES C\1=C\C=C(\C)C/1;
Properties
Chemical formula	C6H8
Molar mass	80.130 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Methylcyclopentadiene describes three isomeric cyclic dialkenes 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.^[1]

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

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, ${\ce {Cp'Fe(PPh3)(CO)I}}$ 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 ${\ce {Cp'Fe(CO)2I}}$ exhibits only two MeC₅H₄ resonances in the ¹H NMR spectrum and three MeC₅H₄ resonances in the ¹³C NMR spectrum.^[2]

References

^ Darkwa, James; Giolando, Dean M.; Murphy, Catherine Jones; Rauchfuss, Thomas B.; Müller, A. (1990). "Bis(η⁵-Methylcyclopentadienyl)Titanium Pentasulfide, Bis(μ-Methylcyclopentadienyl)-Divanadium Pentasulfide, and Bis(μ⁵-Methylcyclopentadienyl)Divanadium Tetrasulfide". Inorg. Synth. 27: 51. doi:10.1002/9780470132586.ch10.
^ Carlton, L.; Johnston, P.; Coville, N. J. (1988). "Substituted cyclopentadienyl complexes. II. Carbon-13 NMR spectra of some ${\ce {[(\eta^5-C5H4Me)Fe(CO)(L)I]}}$ complexes". J. Organomet. Chem. 339 (3): 339–43. doi:10.1016/S0022-328X(00)99395-1. {{cite journal}}: ce stripmarker in |title= at position 77 (help)

References

See also