Folded conformations of N-(aminoalkyl)-9-phenanthrenecarboxamides in the crystal and solution

Frederick D. Lewis*, Eric L. Burch, Charlotte L. Stern

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The molecular structures of three tertiary N-(aminoalkyl)-9-phenanthrenecarboxamides were investigated in solution and the solid state by means of 1H NMR spectroscopy and x-ray crystallography. The tertiary amides exist as a mixture of E and Z isomers in solution and the aminoalkyl groups exist as a mixture extended and folded conformers. A crystalline N-(aminoethyl)amide was obtained as the pure Z isomer in which the phenanthrene and amide planes are nearly perpendicular and the aminoethyl group is folded over the less hindered face of the amide group. Rotation about the Ar-C(O) bond is slow in resolution rendering these molecules chiral on the NMR time-scale. As a consequence, the α-methylene protons display large diasterotopic splittings when the aminoalkyl group is syn to the amide carbonyl. Folded conformations place the Z and E aminoalkyl groups in the deshielding and shielding regions, respectively, of the phenanthrene rings, resulting in large differences in chemical shifts.

Original languageEnglish (US)
Pages (from-to)525-530
Number of pages6
JournalJournal of Physical Organic Chemistry
Volume10
Issue number7
StatePublished - Jul 1 1997

Keywords

  • Folded conformations
  • Molecular structures
  • N-(aminoalkyl)-9-phenanthrenecarboxamides

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

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