Photodissociation reaction of 1,2-diiodoethane in solution: A theoretical and X-ray diffraction study

Qingyu Kong, Joonghan Kim, Maciej Lorenc, Tae Kyu Kim, Hyotcherl Ihee, Michael Wulff

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Abstract

Various molecular species are known to form during the photoreaction of C2H4I2 in the gas phase and in solution. We have studied all species involved in this reaction by ab initio and density functional theory (dFT) calculations: Geometries, energies, and vibrational frequencies of C2H4I2, bridged C 2H4I•, anti C2H4I•, C 2H4, I2, I3-, and the isomer C2H4I-I were calculated. The absorption peaks and oscillator strengths of selected species along the potential energy surface (PES) were calculated using time-dependent DFT and were compared with available experimental results. The calculated PES satisfactorily describes the observed reactions of the photoexcited C2H4I2 molecule. In the gas phase, there is only one reaction pathway: the first C-I bond ruptures followed by a secondary C-I breakage in the haloethyl radical C 2H4I•. In solution, by contrast, another reaction channel, which is energetically more favored over the secondary dissociation, is switched on due to a solvation effect: the bridged C2H 4I• can bind to the free iodine atom to form a C 2H4I-I isomer without any energy barrier. The isomer can then break into C2H4 and I2. The rotational barriers in the gas phase and in solution were also calculated and compared. To provide experimental data on the structure of C2H4I 2 in solution, the ground state structure of C2H 4I2 in methanol was determined from static X-ray diffraction data using 88 keV (A = 0.14 Å) X-rays. The structural parameters are compared with those from the theoretical results.

Original languageEnglish
Pages (from-to)10451-10458
Number of pages8
JournalJournal of Physical Chemistry A
Volume109
Issue number45
DOIs
Publication statusPublished - 2005 Nov 17

Fingerprint

Photodissociation
photodissociation
Isomers
X ray diffraction
Potential energy surfaces
isomers
Gases
vapor phases
diffraction
x rays
potential energy
Energy barriers
Solvation
Vibrational spectra
Discrete Fourier transforms
Iodine
oscillator strengths
Ground state
iodine
Density functional theory

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

Kong, Qingyu ; Kim, Joonghan ; Lorenc, Maciej ; Kim, Tae Kyu ; Ihee, Hyotcherl ; Wulff, Michael. / Photodissociation reaction of 1,2-diiodoethane in solution : A theoretical and X-ray diffraction study. In: Journal of Physical Chemistry A. 2005 ; Vol. 109, No. 45. pp. 10451-10458.
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title = "Photodissociation reaction of 1,2-diiodoethane in solution: A theoretical and X-ray diffraction study",
abstract = "Various molecular species are known to form during the photoreaction of C2H4I2 in the gas phase and in solution. We have studied all species involved in this reaction by ab initio and density functional theory (dFT) calculations: Geometries, energies, and vibrational frequencies of C2H4I2, bridged C 2H4I•, anti C2H4I•, C 2H4, I2, I3-, and the isomer C2H4I-I were calculated. The absorption peaks and oscillator strengths of selected species along the potential energy surface (PES) were calculated using time-dependent DFT and were compared with available experimental results. The calculated PES satisfactorily describes the observed reactions of the photoexcited C2H4I2 molecule. In the gas phase, there is only one reaction pathway: the first C-I bond ruptures followed by a secondary C-I breakage in the haloethyl radical C 2H4I•. In solution, by contrast, another reaction channel, which is energetically more favored over the secondary dissociation, is switched on due to a solvation effect: the bridged C2H 4I• can bind to the free iodine atom to form a C 2H4I-I isomer without any energy barrier. The isomer can then break into C2H4 and I2. The rotational barriers in the gas phase and in solution were also calculated and compared. To provide experimental data on the structure of C2H4I 2 in solution, the ground state structure of C2H 4I2 in methanol was determined from static X-ray diffraction data using 88 keV (A = 0.14 {\AA}) X-rays. The structural parameters are compared with those from the theoretical results.",
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Photodissociation reaction of 1,2-diiodoethane in solution : A theoretical and X-ray diffraction study. / Kong, Qingyu; Kim, Joonghan; Lorenc, Maciej; Kim, Tae Kyu; Ihee, Hyotcherl; Wulff, Michael.

In: Journal of Physical Chemistry A, Vol. 109, No. 45, 17.11.2005, p. 10451-10458.

Research output: Contribution to journalArticle

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T1 - Photodissociation reaction of 1,2-diiodoethane in solution

T2 - A theoretical and X-ray diffraction study

AU - Kong, Qingyu

AU - Kim, Joonghan

AU - Lorenc, Maciej

AU - Kim, Tae Kyu

AU - Ihee, Hyotcherl

AU - Wulff, Michael

PY - 2005/11/17

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N2 - Various molecular species are known to form during the photoreaction of C2H4I2 in the gas phase and in solution. We have studied all species involved in this reaction by ab initio and density functional theory (dFT) calculations: Geometries, energies, and vibrational frequencies of C2H4I2, bridged C 2H4I•, anti C2H4I•, C 2H4, I2, I3-, and the isomer C2H4I-I were calculated. The absorption peaks and oscillator strengths of selected species along the potential energy surface (PES) were calculated using time-dependent DFT and were compared with available experimental results. The calculated PES satisfactorily describes the observed reactions of the photoexcited C2H4I2 molecule. In the gas phase, there is only one reaction pathway: the first C-I bond ruptures followed by a secondary C-I breakage in the haloethyl radical C 2H4I•. In solution, by contrast, another reaction channel, which is energetically more favored over the secondary dissociation, is switched on due to a solvation effect: the bridged C2H 4I• can bind to the free iodine atom to form a C 2H4I-I isomer without any energy barrier. The isomer can then break into C2H4 and I2. The rotational barriers in the gas phase and in solution were also calculated and compared. To provide experimental data on the structure of C2H4I 2 in solution, the ground state structure of C2H 4I2 in methanol was determined from static X-ray diffraction data using 88 keV (A = 0.14 Å) X-rays. The structural parameters are compared with those from the theoretical results.

AB - Various molecular species are known to form during the photoreaction of C2H4I2 in the gas phase and in solution. We have studied all species involved in this reaction by ab initio and density functional theory (dFT) calculations: Geometries, energies, and vibrational frequencies of C2H4I2, bridged C 2H4I•, anti C2H4I•, C 2H4, I2, I3-, and the isomer C2H4I-I were calculated. The absorption peaks and oscillator strengths of selected species along the potential energy surface (PES) were calculated using time-dependent DFT and were compared with available experimental results. The calculated PES satisfactorily describes the observed reactions of the photoexcited C2H4I2 molecule. In the gas phase, there is only one reaction pathway: the first C-I bond ruptures followed by a secondary C-I breakage in the haloethyl radical C 2H4I•. In solution, by contrast, another reaction channel, which is energetically more favored over the secondary dissociation, is switched on due to a solvation effect: the bridged C2H 4I• can bind to the free iodine atom to form a C 2H4I-I isomer without any energy barrier. The isomer can then break into C2H4 and I2. The rotational barriers in the gas phase and in solution were also calculated and compared. To provide experimental data on the structure of C2H4I 2 in solution, the ground state structure of C2H 4I2 in methanol was determined from static X-ray diffraction data using 88 keV (A = 0.14 Å) X-rays. The structural parameters are compared with those from the theoretical results.

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