Study of 25R-NBOHs (R = Br, Cl, Et, I): Thermal stability investigation and presumptive identification by SCXRD and PXRD data

Abstract

New psychoactive substances (NPS) are present in the drug market and can be used as legal substitutes, making enforcement difficult. One of the classes of NPSs is the phenylethylamines, among which 25R-NBOHs (with R being a halogen or an alkyl group) are included. These compounds degrade when subjected to gas chromatography-mass spectrometry (GC–MS), one of the techniques routinely used to identify illicit substances, thereby complicating their identification. This study conducted the identification of NBOH samples using FTIR, XRD, and GC–MS techniques, as well as thermal analysis to obtain information that may assist in the development of new methods for the analysis of these synthetic substances. ATR-FTIR spectra presented characteristic bands of 25R-NBOH compounds (R = Br, Cl, Et, I). The UV–Vis spectra of the 25R-NBOH (R = Br, Cl, I) and 25E-NBOH samples showed a different profile, which may serve as a means to differentiate these compounds. The crystalline structure of the compounds was confirmed by comparing the experimentally obtained diffractograms with the diffraction patterns calculated using data from the Cambridge Crystallographic Data Center (CCDC) database. Thermal analysis indicated that the samples were not pure, confirming the FTIR and XRD analyses, which revealed the presence of impurities and the onset of sample degradation.