Helical chirality in hexamethylene triperoxide diamine

Chunlei Guo, John Persons, Gerard S. Harbison

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The primary explosive hexamethylenetriperoxide diamine has previously been found to exist in the solid state as a racemic mixture of helically chiral, threefold symmetric enantiomers; another enantiomeric pair of low-energy conformers has been predicted, but has never been observed. We show by solution 2D NMR at 14 T, in achiral solution and by addition of chiral shift reagents, that all four optically isomeric conformers coexist at slow equilibrium on the NMR timescale at room temperature, and can be observed. Calculations of the 1H and 13C NMR chemical shifts using gauge-including atomic orbital methods are in excellent agreement with experiment; thermochemical calculation of the free energies in solution are in somewhat worse agreement, but correctly predict the relative stability of the conformers. Analysis of the effects of chiral shift reagents on the NMR spectra suggests that discrimination between chiral isomers is primarily around the molecular equator, around which the enantiomeric gauche O-O linkages are arrayed.

Original languageEnglish (US)
Pages (from-to)832-837
Number of pages6
JournalMagnetic Resonance in Chemistry
Volume44
Issue number9
DOIs
Publication statusPublished - Sep 1 2006

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Keywords

  • Chiral shift reagent
  • Density functional theory
  • Hexamethylene triperoxide diamine
  • NMR

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

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