Cycloheptatrienyl radical

Formula: C₇H₇
Molecular weight: 91.1305
IUPAC Standard InChI: InChI=1S/C7H7/c1-2-4-6-7-5-3-1/h1-7H
IUPAC Standard InChIKey: WIQYRPSOJMHAHR-UHFFFAOYSA-N
CAS Registry Number: 3551-27-7
Chemical structure:
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Gas phase ion energetics data

Go To: Top, Vibrational and/or electronic energy levels, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to C₇H₇⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	198.9	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	191.2	kcal/mol	N/A	Hunter and Lias, 1998	HL

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.390 ± 0.043	LPES	Gunion, Karney, et al., 1996	Vertical Detachment Energy: 0.64 eV; B
0.49 ± 0.13	D-EA	Bartmess, Scott, et al., 1979	value altered from reference due to change in acidity scale; B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
6.28 ± 0.02	PE	Koenig and Chang, 1978	LLK
6.74 ± 0.05	EI	Hvistendahl, Undheim, et al., 1973	LLK
6.236 ± 0.005	PI	Elder and Parr, 1969	RDSH
6.24 ± 0.01	S	Thrush and Zwolenik, 1963	RDSH
6.6 ± 0.1	EI	Harrison, Honnen, et al., 1960	RDSH

Vibrational and/or electronic energy levels

Go To: Top, Gas phase ion energetics data, References, Notes

Data compiled by: Marilyn E. Jacox

State: 7f

Energy (cm^-1)	Med.	References


T_o = 47888	gas	Johnson, 1991

State: 6f

Energy (cm^-1)	Med.	References


T_o = 47060	gas	Johnson, 1991

State: 5d

Energy (cm^-1)	Med.	References


T_o = 45991	gas	Thrush and Zwolenik, 1963

State: 5f

Energy (cm^-1)	Med.	References


T_o = 45696	gas	Johnson, 1991

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁'	2	Ring breathing	861		gas	MPI	Johnson, 1991
e₃'	18	CCC deform.	763	H	gas	MPI	Johnson, 1991
e₃	20	OPLA	635	H	gas	MPI	Johnson, 1991

State: 5p

Energy (cm^-1)	Med.	References


T_o = 45138	gas	Johnson, 1991

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


e₃'	18	CCC deform.	764	H	gas	MPI	Johnson, 1991

State: 4d

Energy (cm^-1)	Med.	References


T_o = 43654	gas	Thrush and Zwolenik, 1963

State: 4f

Energy (cm^-1)	Med.	References


T_o = 43135	gas	Johnson, 1991

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁'	2	Ring breathing	859		gas	MPI	Johnson, 1991
e₃'	18	CCC deform.	768	H	gas	MPI	Johnson, 1991
e₃	20	OPLA	643	H	gas	MPI	Johnson, 1991

State: 4p

Energy (cm^-1)	Med.	References


T_o = 41920	gas	Johnson, 1991

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁'	2	Ring breathing	861		gas	MPI	Johnson, 1991
e₃'	18	CCC deform.	762	H	gas	MPI	Johnson, 1991
e₃	20	OPLA	642	H	gas	MPI	Johnson, 1991

State: 3d

Energy (cm^-1)	Med.	References


T_o = 38500	gas	Thrush and Zwolenik, 1963

State: 3p

Energy (cm^-1)	Med.	References


T_o = 35186	gas	Johnson, 1991

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁'	2	Ring breathing	866		gas	MPI	Johnson, 1991
e₃'	18	CCC deform.	775	H	gas	MPI	Johnson, 1991
e₃	20	OPLA	648	H	gas	MPI	Johnson, 1991

State: A

Energy (cm^-1)	Med.	References


T_o = 25719 ± 3	gas	Pino, Guthe, et al., 2002

Approximate type of mode	cm^-1	Med.	Method	References


	1620 ± 10	gas	MPI	Pino, Guthe, et al., 2002
	1275 ± 10	gas	MPI	Pino, Guthe, et al., 2002
Ring breathing	854 ± 5	gas	MPI	Pino, Guthe, et al., 2002

State: X

cm^-1		Med.	Method	References


1691	w m	gas	FE	Satink, Meijer, et al., 2003
1561	w m	gas	FE	Satink, Meijer, et al., 2003
1444	w m	gas	FE	Satink, Meijer, et al., 2003
1189	w	gas	FE	Satink, Meijer, et al., 2003
969	w m	gas	FE	Satink, Meijer, et al., 2003
943	w	gas	FE	Satink, Meijer, et al., 2003
892	w	gas	FE	Satink, Meijer, et al., 2003
880	w m	gas	FE	Satink, Meijer, et al., 2003
769	m	gas	FE	Satink, Meijer, et al., 2003
718	w m	gas	FE	Satink, Meijer, et al., 2003
626	s	gas	FE	Satink, Meijer, et al., 2003
611	s	gas	FE	Satink, Meijer, et al., 2003
515	s	gas	FE	Satink, Meijer, et al., 2003
418	w	gas	FE	Satink, Meijer, et al., 2003

Additional references: Jacox, 1994, page 394

Notes

Weak

Medium

Strong

(1/2)(2ν)

Energy separation between the v = 0 levels of the excited and electronic ground states.

References

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Gunion, Karney, et al., 1996
Gunion, R.F.; Karney, W.; Wenthold, P.G.; Borden, W.T.; Lineberger, W.C., Ultraviolet Photoelectron Spectroscopy of Some C7H7- Isomers: Quadricyclanide, Norbornadienide, Cycloheptatrienide, and 1,6-Heptadiynide, J. Am. Chem. Soc., 1996, 118, 21, 5074, https://doi.org/10.1021/ja954026f . [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Koenig and Chang, 1978
Koenig, T.; Chang, J.C., Helium(I) photoelectron spectrum of tropyl radical, J. Am. Chem. Soc., 1978, 100, 2240. [all data]

Hvistendahl, Undheim, et al., 1973
Hvistendahl, G.; Undheim, K.; Gyorosi, P., Mass spectrometry of tropylium halides, Org. Mass Spectrom., 1973, 7, 903. [all data]

Elder and Parr, 1969
Elder, F.A.; Parr, A.C., Photoionization of the cycloheptatrienyl radical, J. Chem. Phys., 1969, 50, 1027. [all data]

Thrush and Zwolenik, 1963
Thrush, B.A.; Zwolenik, J.J., Spectrum of the tropyl radical, Faraday Discuss. Chem. Soc., 1963, 35, 196. [all data]

Harrison, Honnen, et al., 1960
Harrison, A.G.; Honnen, L.R.; Dauben, H.J., Jr.; Lossing, F.P., Free radicals by mass spectrometry. XX. Ionization potentials of cyclopentadienyl and cycloheptatrienyl radicals, J. Am. Chem. Soc., 1960, 82, 5593. [all data]

Johnson, 1991
Johnson, R.D., III, Excited electronic states of the tropyl (cyclo-C7H7 ) radical, J. Chem. Phys., 1991, 95, 10, 7108, https://doi.org/10.1063/1.461387 . [all data]

Pino, Guthe, et al., 2002
Pino, T.; Guthe, F.; Ding, H.; Maier, J.P., Gas-Phase Electronic Spectrum of the Tropyl C, J. Phys. Chem. A, 2002, 106, 42, 10022, https://doi.org/10.1021/jp020910y . [all data]

Satink, Meijer, et al., 2003
Satink, R.G.; Meijer, G.; von Helden, G., Infrared Spectroscopy of Neutral C, J. Am. Chem. Soc., 2003, 125, 51, 15714, https://doi.org/10.1021/ja038329i . [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]

Notes

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

Symbols used in this document:

EA Electron affinity
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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