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Issue 5, 1998
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Properties of tetramethyleneethane (TME) as revealed by ion chemistry and ion photoelectron spectroscopy

Abstract

The negative ion chemistry and photoelectron spectra of [CH2[double bond, length half m-dash]C(CH3)–C(CH2)2] and [(CH2)2C–C(CH2)2] have been studied. The negative ion photoelectron spectra reveal the tetramethyleneethane diradical, TME, to have two low-lying electronic states, [X with combining tilde] and ã. The ground [X with combining tilde] state is assigned as [TME] 1A and the excited ã state as [TME] 3B1. The energy separation between these states is about 2 kcal mol–1; ΔE 3B1 ← [X with combining tilde]1A] ≊ 0.1 eV. The experimental electron affinities of the neutrals are: Eea[CH2[double bond, length half m-dash]C(CH3)– C(CH2)2] = 0.654 ± 0.010 eV and Eea[(CH2)2C–C(CH2)2] = 0.855 ± 0.010 eV. The experimental gas phase acidities are: ΔacidH298[CH2[double bond, length half m-dash]C(CH3)–C(CH2)CH2–H] = 388 ± 3 kcal mol–1 and ΔacidH298[(CH2)2C–C(CH2)CH2–H] = 388 ± 4 kcal mol–1. These findings can be used to establish the bond energies and heats of formation: DH298[CH2[double bond, length half m-dash]C(CH3)–C(CH2)CH2–H] = 90 ± 3 kcal mol–1 and ΔfH298[(CH2)2C–C(CH3)[double bond, length half m-dash]CH2] = 48 ± 3 kcal mol–1; DH298[(CH2)2C–C(CH2)CH2–H] = 94 ± 4 kcal mol–1 and ΔfH298[(CH2)2C–C(CH2)2] = 90 ± 5 kcal mol–1.

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Article type: Paper
DOI: 10.1039/A707322D
J. Chem. Soc., Perkin Trans. 2, 1998, 1015-1022

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    Properties of tetramethyleneethane (TME) as revealed by ion chemistry and ion photoelectron spectroscopy

    E. P. Clifford, P. G. Wenthold, W. Carl Lineberger, G. Barney Ellison, C. X. Wang, J. J. Grabowski, F. Vila and K. D. Jordan, J. Chem. Soc., Perkin Trans. 2, 1998, 1015
    DOI: 10.1039/A707322D

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