Cyclooctatetraenes Tetrakis-Annelated with α-Dithio- or α-Diselenocarbonyl Groups: Diradicals Predicted To Have Ground States with 10 π Electrons in the Eight-Membered Ring and Two-Center, Three-Electron, σ Bonds between Two Pairs of Chalcogen Atoms

Description:

Article on cyclooctatetraenes tetrakis-annelated with α-dithio- or α-diselenocarbonyl groups.

Creator(s):
Creation Date: February 12, 2010
Partner(s):
UNT College of Arts and Sciences
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UNT Scholarly Works
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Creator (Author):
Zhou, Xin

University of North Texas

Creator (Author):
Hrovat, David A.

University of North Texas

Creator (Author):
Borden, Weston T., 1943-

University of North Texas

Publisher Info:
Publisher Name: American Chemical Society
Place of Publication: [Washington, DC]
Date(s):
  • Creation: February 12, 2010
Description:

Article on cyclooctatetraenes tetrakis-annelated with α-dithio- or α-diselenocarbonyl groups.

Degree:
Department: Chemistry
Note:

Reprinted with permission from the Journal of Physical Chemistry. Copyright 2010 American Chemical Society.

Note:

Abstract: (U)B3LYP calculations with the 6-31+G(d) and 6-311+G(2df) basis sets have been carried out on cyclooctatetraenes 6 and 7, in which the COT ring is tetrakis-annelated with α-dithio- or α-diselenocarbonyl groups. Transferring two electrons from the high-lying b1g and eu σ MOs in 6 and 7 into the unoccupied, nonbonding, COT π orbital is computed to be energetically favorable. The lowest D4h electronic state is calculated to be 3Eu, which formally contains 10 π electrons in the eight-membered ring and has two unpaired electrons in σ MOs. The 3Eu state undergoes a first-order Jahn-Teller distortion to form 6d and 7d, in which the pair of one-electron holes in the σ MOs is stabilized by the formation of two, two-center, three-electron bonds between pairs of chalcogen atoms that are diagonally across the eight-membered ring from each other. The corresponding open-shell singlets are computed to be about 1 kcal/mol lower in energy than the Jahn-Teller distorted triplets. Molecules 6i and 7i, in which the C-C bond in one four-membered ring is cleaved, are computed to be lower in energy than 6d and 7d. However, a substantial barrier is predicted to separate each of the two pairs of isomers so that 6d and 7d should, at least in principle, be isolable.

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8 p.

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Subject(s):
Keyword(s): cyclooctatetraenes | electrons | bonds
Source: Journal of Physical Chemistry A, 2010, Washington DC: American Chemical Society, pp. 3683-3690
Partner:
UNT College of Arts and Sciences
Collection:
UNT Scholarly Works
Identifier:
  • DOI: 10.1021/jp911705y
  • ARK: ark:/67531/metadc71813
Resource Type: Article
Format: Text
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Access: Public
Citation:
Publication Title: Journal of Physical Chemistry A
Volume: 114
Page Start: 3683
Page End: 3690
Peer Reviewed: Yes