The geometrical molecular structures, atomic charges, frontier molecular orbitals, and UV–visible electronic data of analgesic drugs carfentanil and acetylfentanyl were computed using quantum chemical code. In addition, NMR (¹H and ¹³C) chemical shifts, harmonic vibrational wavenumbers, and the corresponding vibrational assignments were proposed on the basis of potential energy distribution. The calculations were carried out at Becke-3-Lee–Yang–Parr (B3LYP) functional with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) using the 6–311 + + G(d,p) basis set. The piperidine rings of the two molecules adopt a more stable chair conformation of a six-membered ring structure with slight distortion at the point of substitution. This shows that the piperidine moiety of the carfentanil and acetylfentanyl have similar geometric parameters and thus support the hypothesis that the piperidine ring in these molecules is the primary structural feature that is responsible for their analgesic activities. In addition, the introduction of the carbomethoxy (-COCH₃) group into the piperidine ring of fentanyl has little or no effect on the electronic properties of this class of molecules. The theoretical results were successfully compared with similar piperidine-based analgesic drugs fentanyl and available experimental data. This research gives precise and invaluable information that will help in the structural elucidation of analogs of fentanyl that could be used in the development of analytical methods for the accurate and reliable detection and monitoring of these important molecules.

使用量子化学代码计算了镇痛药卡芬太尼和乙酰芬太尼的几何分子结构、原子电荷、前沿分子轨道和紫外-可见电子数据。此外，核磁共振（¹ H 和¹³C) 基于势能分布提出了化学位移、谐波振动波数和相应的振动分配。计算是在 Becke-3-Lee-Yang-Parr (B3LYP) 泛函与密度泛函理论 (DFT) 和瞬态密度泛函理论 (TD-DFT) 使用 6-311 + + G(d,p ) 基组。两个分子的哌啶环采用更稳定的六元环结构椅子构象，在取代点处略有变形。这表明卡芬太尼和乙酰芬太尼的哌啶部分具有相似的几何参数，因此支持这些分子中的哌啶环是导致其镇痛活性的主要结构特征的假设。此外，₃ ) 芬太尼哌啶环中的基团对此类分子的电子性质影响很小或没有影响。将理论结果与同类哌啶类镇痛药芬太尼和现有实验数据进行了比较。这项研究提供了精确和宝贵的信息，有助于芬太尼类似物的结构解析，这些信息可用于开发分析方法，以准确可靠地检测和监测这些重要分子。