The 1H T1 dispersion curve of fentanyl citrate to identify NQR parameters

Abstract

We report the ¹H $T_1$ dispersion curve between 0 and 5 ​MHz for the synthetic opioid fentanyl citrate (C₂₈H₃₆N₂O₈). The structures in the curve can be used to estimate the ¹⁴N nuclear quadrupole resonance (NQR) frequencies of the material. Density functional theory predictions of the NQR parameters of several fentanyl citrate compounds are also reported. The predictions for the aniline nitrogen are consistent with structures in the observed $T_1$ data. To help interpret the fentanyl citrate results the $T_1$ dispersion curve for the explosive ammonium nitrate is also presented.