- Density functional theory and X-ray investigations of P- and M-hexamethylene triperoxide diamine and its dialdehyde derivative
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Recently, we carried out a density functional theory B3LYP/6-31+G(d) study of hexamethylene triperoxide diamine (HMTD) in order to elucidate the unusual, nearly planar, sp2 hybridization of the two bridgehead nitrogen atoms, each bonded to the three CH2 groups. We postulated that extended bonding orbitals between peroxide oxygens results in charge delocalization which decreases lone-pair repulsion and compensates the energy loss due to the sp3 to sp2 hybridization change on the nitrogen atoms. We have reexamined the crystal structure of HMTD by performing low-temperature, single-crystal X-ray studies, and we have determined that the unit cell contains a 50-50 racemic mixture of enantiomeric forms of HMTD, showing disorder about the mirror plane. At the low temperature, all hydrogen atoms were located and resolved, which was not previously possible. We have also crystallized and performed low-temperature X-ray analysis of a never previously reported dialdehyde form of HMTD, tetramethylene diperoxide diamine dialdehyde (TMDDD), which reveals enantiomers present in the unit cell without disorder. B3LYP density functional theory studies of HMTD and TMDDD are presented, as well as a transition state investigation of possible thermal interconversion of the HMTD enantiomers.
- Wierzbicki, Andrzej,Salter, E. Alan,Cioffi, Eugene A.,Stevens, Edwin D.
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- Investigation of isotopic linkages between precursor materials and the improvised high explosive product hexamethylene triperoxide diamine
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The results of isotope ratio mass spectrometry (IRMS) on hexamethylene triperoxide diamine (HMTD) and its precursor hexamethylenetetramine (hexamine) is presented. HMTD was prepared from hexamine using several different sources of hexamine under both controlled laboratory conditions and in field experiments that represent the less controlled conditions that are likely to be observed in forensic casework scenarios. Precursor and product carbon isotope δ values consistently fit a linear relationship regardless of precursor or conditions. The magnitude of the isotope fractionation observed is affected by the efficiency of the reaction, with greater yielding reactions giving rise to HMTD with δ values more similar to the precursor material than lower yielding reactions. Nitrogen isotope δ values comparing precursor with product show some linearity when the reaction conditions are carefully controlled; however, results indicate a poor fit with linearity when synthesis conditions are more variable. Despite the greater variation, the HMTD product consistently has a more positive δ value compared with the hexamine precursor. The results observed from these experiments suggest hexamine reacts to form HMTD in a 1:1 ratio. Having prepared multiple HMTD samples from various precursors using a range of experimental conditions, we have observed results that may be useful in forensic investigations of improvised explosive materials. Published 2012 by the American Chemical Society.
- Lock, Claire M.,Brust, Hanneke,Van Breukelen, Martin,Dalmolen, Jan,Koeberg, Mattijs,Stoker, Davey A.
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- Helical chirality in hexamethylene triperoxide diamine
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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. Copyright
- Guo, Chunlei,Persons, John,Harbison, Gerard S.
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- Enhanced electrospray ionization mass spectrometric detection of hexamethylene triperoxide diamine (HMTD) after oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD)
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Rationale Hexamethylene triperoxide diamine (HMTD) is one of the peroxide-based explosives that are difficult to detect using standard analytical methodologies. Methods It was analyzed by electrospray ionization mass spectrometry (ESI-MS) on a UPLC-TOF instrument. Alkali metal salts were used to promote the formation of ions. Results In the full scan positive ion mode a 3 ng (13 pmol) limit of detection was achieved if [HMTD + Me]+ ions (Me = Li, Na, K) were detected. It was found that HMTD easily undergoes oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD) in the source as well as in the samples. TMDDD can be detected as [TMDDD + Me]+ ions, but better ionization efficiency leads to the detection limit of TMDDD at the 2 pg (0.01 pmol) level. In butyl acetate the yield of oxidation of HMTD to TMDDD reaches 25% within 20 min at 120 C, which offers a simple way of improving the detection limit of HMTD by two orders of magnitude. Conclusions A simple procedure of detection of HMTD that matches the most sensitive methods available was developed. It uses standard equipment available in many laboratories. It was shown that the frequently reported [HMTD-H]+ cation observed by various authors was in fact a misinterpretation of the results, and should be attributed to [TMDDD + H]+.
- Krawczyk, Tomasz
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- Differentiation among peroxide explosives with an optoelectronic nose
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Forensic identification of batches of homemade explosives (HME) poses a difficult analytical challenge. Differentiation among peroxide explosives is reported herein using a colorimetric sensor array and handheld scanner with a field-appropriate sampling protocol. Clear discrimination was demonstrated among twelve peroxide samples prepared from different reagents, with a classification accuracy >98%.
- Li, Zheng,Bassett, Will P.,Askim, Jon R.,Suslick, Kenneth S.
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supporting information
p. 15312 - 15315
(2015/10/20)
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- Detection of impurities in organic peroxide explosives from precursor chemicals
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Previous analyses of organic peroxide explosives have focussed on identification of the explosive itself, and were performed using explosive samples synthesized from laboratory-grade precursors. In this work, analytical studies of precursors obtained from retail outlets identified compounds that could be carried over into the explosives as impurities during synthesis. Forensic and intelligence information may be gained by the identification of possible precursor impurities in explosive samples. This hypothesis was tested using triacetone triperoxide and hexamethylene triperoxide diamine prepared from domestically available off-the-shelf precursors. Gas chromatographymass spectrometry analysis showed that compounds originating from such precursors could be detected in the organic peroxide samples at different stages in their purification. Furthermore, some compounds could also be detected in the residues of samples that had been subjected to thermal initiation.
- Partridge, Andrew,Walker, Stewart,Armitt, David
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p. 30 - 37
(2010/06/12)
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- Amine Peroxides as Potential Antimalarials
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Six model amine peroxides (4-9) were synthesized as targeted antimalarial oxidants.They were approximately 1 order of magnitude more potent than tert-butyl hydroperoxide (3) in vitro against Plasmodium falciparum, but like 3, they were inactive in vivo against Plasmodium berghei.
- Vennerstrom, Jonathan L.
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