Dpto. de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco-UPV/EHU, Bo Sarriena s/n, Leioa 48940, Spain.
J Chem Phys. 2012 Aug 21;137(7):074303. doi: 10.1063/1.4743960.
Propofol (2,6-di-isopropylphenol) is probably the most widely used general anesthetic. Previous studies focused on its complexes containing 1 and 2 water molecules. In this work, propofol clusters containing three water molecules were formed using supersonic expansions and probed by means of a number of mass-resolved laser spectroscopic techniques. The 2-color REMPI spectrum of propofolmiddle dot(3) contains contributions from at least two conformational isomers, as demonstrated by UV/UV hole burning. Using the infrared IR/UV double resonance technique, the IR spectrum of each isomer was obtained both in ground and first excited electronic states and interpreted in the light of density functional theory (DFT) calculations at M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels. The spectral analysis reveals that in both isomers the water molecules are forming cyclic hydrogen bond networks around propofol's OH moiety. Furthermore, some evidences point to the existence of isomerization processes, due to a complicated conformational landscape and the existence of multiple paths with low energy barriers connecting the different conformers. Such processes are discussed with the aid of DFT calculations.
丙泊酚（2,6-二异丙基苯酚）可能是最广泛使用的全身麻醉剂。以前的研究集中在含有 1 和 2 个水分子的它的配合物上。在这项工作中，使用超音速膨胀形成了含有三个水分子的丙泊酚簇，并通过多种质量分辨激光光谱技术进行了探测。丙泊酚中圆点(3)的双色 REMPI 光谱显示，至少存在两种构象异构体，这一点通过紫外/紫外光烧孔得到了证明。利用红外 IR/UV 双共振技术，在基态和第一激发电子态下获得了每个异构体的红外光谱，并根据密度泛函理论（DFT）计算在 M06-2X/6-311++G(d,p)和 B3LYP/6-311++G(d,p)水平进行了解释。光谱分析表明，在两种异构体中，水分子都在丙泊酚的 OH 部分周围形成环状氢键网络。此外，由于复杂的构象景观和连接不同构象体的低能垒的多条路径的存在，存在一些证据表明存在异构化过程。这些过程在 DFT 计算的帮助下进行了讨论。
