Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Calle Doctor Mergelina, s/n, E-47011 Valladolid, Spain.
Phys Chem Chem Phys. 2010 Sep 7;12(33):9624-31. doi: 10.1039/c002123g. Epub 2010 May 27.
Most of the volatile haloorganic compounds used as anesthetics exhibit a heavy-atom frame large enough to allow for conformational changes. Even in the absence of directed intermolecular interactions, only some or just one of the possible conformations might have an appreciable abundance. In this realm, the structure of the anesthetic haloether sevoflurane (CH(2)F-O-CH(CF(3))(2)) has been resolved using Fourier-transform microwave (FT-MW) spectroscopy in a supersonic-jet expansion. In isolated conditions sevoflurane adopts a single conformation characterized by a gauche fluoromethoxy group and a near-symmetric orientation of the isopropyl group with respect to the ether plane (cis H-C(ipr)-O-C(F)). Substitution and effective structures have been calculated from the rotational spectra of all (13)C and (18)O monosubstituted isotopic species observed in natural abundance. The electric dipole moment components were determined from additional Stark effect measurements. The experimental structures and rotational data are compared with those obtained from supporting ab initio predictions using MP2 calculations and the B3LYP hybrid functional.
大多数用作麻醉剂的挥发性卤代有机化合物都具有足够大的重原子骨架，允许构象发生变化。即使在没有定向分子间相互作用的情况下，也只有部分或只有一种可能的构象可能具有可观的丰度。在这个领域，卤代醚七氟烷（CH(2)F-O-CH(CF(3))(2)）的结构已经使用傅里叶变换微波（FT-MW）光谱在超音速射流膨胀中得到解决。在分离条件下，七氟烷采用单一构象，其特征是 gauche 氟甲氧基和异丙基相对于醚平面的近乎对称取向（顺式 H-C(ipr)-O-C(F)）。取代基和有效结构是从所有观察到的天然丰度的（13）C 和（18）O 单取代同位素物种的旋转光谱中计算出来的。电偶极矩分量是通过附加的斯塔克效应测量确定的。实验结构和旋转数据与使用 MP2 计算和 B3LYP 混合泛函的支持从头预测获得的结果进行了比较。
