The synthetic drug 3,4-methylenedioxy-N-methylamphetamine (MDMA), also known as ecstasy, is one of the most abused dance drugs spread around the world. The number of seizures of ecstasy tablets increases every year. As MDMA is a chiral substance with one chiral center, it may occur as two enantiomers. These enantiomers have different physiological effects, therefore the reliable detection of individual enantiomers and a detailed structural description are highly desirable. In this work, the 3D structure of MDMA in solution was investigated by vibrational circular dichroism and electronic circular dichroism supplemented by conventional infrared and ultraviolet absorption spectroscopies. The obtained results were supported by density functional theory (DFT) calculations using different levels of theory. Initially, sixty-four starting geometries were optimized at the B3LYP/6-31G(d) level including the solvent effects. Four stable conformers were further reoptimized at higher levels of theory and the spectra were also simulated. The experimental and the calculated spectra were compared via the similarity index. The spectra comparison showed very good agreement, which enabled us to describe the molecular structure of MDMA in detail.

合成药3,4-亚甲二氧基-N-甲基苯丙胺（MDMA），也被称为摇头丸，是世界上滥用最广泛的舞蹈药物之一。摇头丸的缉获量每年都在增加。由于MDMA是具有一个手性中心的手性物质，它可能以两种对映异构体的形式出现。这些对映异构体具有不同的生理作用，因此非常需要可靠地检测各个对映异构体并进行详细的结构描述。在这项工作中，通过振动圆二色性和电子圆二色性并辅以常规的红外和紫外吸收光谱研究了溶液中MDMA的3D结构。所获得的结果得到使用不同理论水平的密度泛函理论（DFT）计算的支持。原来，在包括溶剂效应在内的B3LYP / 6-31G（d）水平上优化了64种起始几何形状。在更高的理论水平上进一步重新优化了四个稳定的构象异构体，并对光谱进行了模拟。比较了实验光谱和计算光谱通过相似性指标。光谱比较显示出很好的一致性，这使我们能够详细描述MDMA的分子结构。