Aryl ring twists in tris(2,6-dimethoxyphenyl)-z tripod ethers

X-ray analysis of an isostructural series of triarylpropellers

Scott J. Stoudt, Prakash Gopalan, Bart Kahr, James E. Jackson

Research output: Contribution to journalArticle

Abstract

Tris(2,6-dimethoxyphenyl)amine has been synthesized and its molecular and crystal structure determined by X-ray diffraction. This structure completes the series of isosteric compounds Ar3Z, where Z=B, C., N, and Ar=2,6-dimethoxyphenyl. Structures for the tris(2-methoxy-6-methylphenyl) borane and tris(2,6-dimethoxyphenyl)methyl cation triiodide (Ar3C+I3-) are also reported. The Ar3B and Ar3N structures are isomorphous. The triiodide and the earlier reported tetrafluoroborate salt (Ar3C+BF4-) are also quite similar, as are the two boranes above and the known trimesitylborane, which all tend toward D3 symmetric conformations. In contrast, the radical Ar3C., intermediate between Ar3B and Ar3N, is markedly unsymmetrical. Taken together, these findings support an earlier conjecture that the solid-state conformation of Ar3C. does not represent a minimum energy structure for the free radical in solution. Crystal seeding by radical oxidation products is offered as an explanation for the radical's markedly unsymmetrical crystal geometry.

Original languageEnglish (US)
Pages (from-to)335-340
Number of pages6
JournalStructural Chemistry
Volume5
Issue number5
DOIs
StatePublished - Oct 1994

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Boranes
tripods
Ethers
X ray analysis
Conformations
ethers
boranes
X-Rays
Crystals
rings
Molecular Structure
X-Ray Diffraction
Molecular structure
Free Radicals
Amines
Cations
x rays
Salts
Crystal structure
inoculation

Keywords

  • triarylamine
  • triarylborane
  • triarylmethyl radical
  • triarylpropellers
  • Tripod ethers

ASJC Scopus subject areas

  • Chemistry(all)
  • Structural Biology

Cite this

Aryl ring twists in tris(2,6-dimethoxyphenyl)-z tripod ethers : X-ray analysis of an isostructural series of triarylpropellers. / Stoudt, Scott J.; Gopalan, Prakash; Kahr, Bart; Jackson, James E.

In: Structural Chemistry, Vol. 5, No. 5, 10.1994, p. 335-340.

Research output: Contribution to journalArticle

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abstract = "Tris(2,6-dimethoxyphenyl)amine has been synthesized and its molecular and crystal structure determined by X-ray diffraction. This structure completes the series of isosteric compounds Ar3Z, where Z=B, C., N, and Ar=2,6-dimethoxyphenyl. Structures for the tris(2-methoxy-6-methylphenyl) borane and tris(2,6-dimethoxyphenyl)methyl cation triiodide (Ar3C+I3-) are also reported. The Ar3B and Ar3N structures are isomorphous. The triiodide and the earlier reported tetrafluoroborate salt (Ar3C+BF4-) are also quite similar, as are the two boranes above and the known trimesitylborane, which all tend toward D3 symmetric conformations. In contrast, the radical Ar3C., intermediate between Ar3B and Ar3N, is markedly unsymmetrical. Taken together, these findings support an earlier conjecture that the solid-state conformation of Ar3C. does not represent a minimum energy structure for the free radical in solution. Crystal seeding by radical oxidation products is offered as an explanation for the radical's markedly unsymmetrical crystal geometry.",
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AB - Tris(2,6-dimethoxyphenyl)amine has been synthesized and its molecular and crystal structure determined by X-ray diffraction. This structure completes the series of isosteric compounds Ar3Z, where Z=B, C., N, and Ar=2,6-dimethoxyphenyl. Structures for the tris(2-methoxy-6-methylphenyl) borane and tris(2,6-dimethoxyphenyl)methyl cation triiodide (Ar3C+I3-) are also reported. The Ar3B and Ar3N structures are isomorphous. The triiodide and the earlier reported tetrafluoroborate salt (Ar3C+BF4-) are also quite similar, as are the two boranes above and the known trimesitylborane, which all tend toward D3 symmetric conformations. In contrast, the radical Ar3C., intermediate between Ar3B and Ar3N, is markedly unsymmetrical. Taken together, these findings support an earlier conjecture that the solid-state conformation of Ar3C. does not represent a minimum energy structure for the free radical in solution. Crystal seeding by radical oxidation products is offered as an explanation for the radical's markedly unsymmetrical crystal geometry.

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