Methylenecyclopropene

Formula: C₄H₄
Molecular weight: 52.0746
IUPAC Standard InChI: InChI=1S/C4H4/c1-4-2-3-4/h2-3H,1H2
IUPAC Standard InChIKey: GOSMMPKSWSOPRZ-UHFFFAOYSA-N
CAS Registry Number: 4095-06-1
Chemical structure:
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Gas phase ion energetics data

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Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman

View reactions leading to C₄H₄⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_{(+) ion}	289.	kcal/mol	N/A	N/A

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.15 ± 0.03	PE	Staley and Norden, 1989	LL
8.41 ± 0.05	PE	Staley and Norden, 1989	Vertical value; LL

Vibrational and/or electronic energy levels

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Data compiled by: Marilyn E. Jacox

State: X

cm^-1		Med.	Method	References


1770	vs	Ar	IR	Billups, Lin, et al., 1984 Maier, Hoppe, et al., 1984
1519	m	Ar	IR	Billups, Lin, et al., 1984 Maier, Hoppe, et al., 1984
754	s	Ar	IR	Billups, Lin, et al., 1984 Maier, Hoppe, et al., 1984
664	m	Ar	IR	Billups, Lin, et al., 1984 Maier, Hoppe, et al., 1984

Additional references: Jacox, 1994, page 377; Norden, Staley, et al., 1986; Bogey, 1991

Notes

Medium

Strong

Very strong

References

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Staley and Norden, 1989
Staley, S.W.; Norden, T.D., Structure and energetics of C₄H₄⁺ in the gas phase. Photoelectron spectrum of methylenecyclopropene, J. Am. Chem. Soc., 1989, 111, 445. [all data]

Billups, Lin, et al., 1984
Billups, W.E.; Lin, L-J.; Casserly, E.W., Synthesis of methylenecyclopropene, J. Am. Chem. Soc., 1984, 106, 12, 3698, https://doi.org/10.1021/ja00324a064 . [all data]

Maier, Hoppe, et al., 1984
Maier, G.; Hoppe, M.; Lanz, K.; Reisenauer, H.P., Neue wege zum cyclobutadien und methylencyclopropen, Tetrahedron Lett., 1984, 25, 49, 5645, https://doi.org/10.1016/S0040-4039(01)91402-9 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Norden, Staley, et al., 1986
Norden, T.D.; Staley, S.W.; Taylor, W.H.; Harmony, M.D., Electronic character of methylenecyclopropene: microwave spectrum, structure, and dipole moment, J. Am. Chem. Soc., 1986, 108, 25, 7912, https://doi.org/10.1021/ja00285a005 . [all data]

Bogey, 1991
Bogey, M., M. Cordonnier, 1991, J.-L. Destombes, J.-M.. Denis, and j.-C. Guillemin, J. Mol. Spectrosc. 149, 230. [all data]

Notes

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Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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