The unusual solid state structure of heroin hydrochloride monohydrate and its selective detection using NQR spectroscopy

Balchin, E.; Malcolme-Lawes, D.J.; Rowe, M.D.; Smith, J.A.S.; Bearpark, M.J.; Steed, J.W.; Wu, W.M.; Horsewill, A.J.; Stephenson, D.

Abstract

Heroin hydrochloride monohydrate, the normal crystalline form of this material, has been studied by X-ray crystallography, nuclear quadrupole resonance spectroscopy, and theoretical calculations. The X-ray data at 120 K could be refined in either of the two space groups P4(1) or P4(1)2(1)2 with the latter higher symmetry form being the more likely, but for the NQR spectra at 4.2 K the doublet structure suggests that a slight symmetry breaking has ocurrred, which lowers the symmetry to P4(1). The crystals have the unusual unit cell dimensions of a = b = 7.5335(2) Angstrom, c = 71.976(4) Angstrom, with Z = 8 (and Z' = 2 in P4(1)); the molecules are arranged on a four-fold helix of pitch 72.0 Angstrom with its axis parallel to the c axis, requiring a total of eight molecules in order to complete one turn. As in the free base the nitrogen ring system of the N-protonated heroin molecule has a chair conformation; in P4(1) the N-H hydrogen is bonded to a Cl- with N-H...Cl distances of 3.056(15) and 3.095(14) Angstrom and each Cl- ion is also hydrogen bonded to two water molecules. N-14 and Cl-35 quadrupole resonance frequencies have been observed in both the pure material and material from a drugs seizure by two double resonance techniques; in cross-relaxation spectra, a broad Cl-35,Cl-37 resonance is found near 1.95 MHz at room temperature and an analysis of the line shape predicts an average quadrupole coupling constant for the two ions of 3.817 MHz and an asymmetry parameter of 0.4. In double resonance by level crossing experiments, N-14 doublets are observed near 0.965 and 1.035 MHz at 4.2 K, predicting a mean quadrupole coupling constant of 1.333 MHz and an asymmetry parameter of 0.158. A doublet Cl-35 signal is also observed at 1.965 MHz. The doublet patterns observed are consistent with a P4(1) space group at 4.2 K. The similarity of the NQR data from the pure sample and the seizure confirms that the illicit sample is of the helical monohydrate, suggesting that these methods can be used to detect the narcotic in real situations. Theoretical calculations with Gaussian at the HF/6-31+ G* level for two molecules at the configurations they adopt in the solid state are in reasonable agreement with these conclusions for N-14 and one of the Cl-35 ions.

Citation

Balchin, E., Malcolme-Lawes, D., Rowe, M., Smith, J., Bearpark, M., Steed, J., …Stephenson, D. (2004). The unusual solid state structure of heroin hydrochloride monohydrate and its selective detection using NQR spectroscopy. New Journal of Chemistry, 28(11), 1309-1314

• Journal Article Type: Article
• Publication Date: 2004
• Journal: New Journal of Chemistry
• Print ISSN: 1144-0546
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 11
• Pages: 1309-1314
• Public URL: https://durham-repository.worktribe.com/output/1571622