Seifert Nathan A, Pérez Cristóbal, Neill Justin L, Pate Brooks H, Vallejo-López Montserrat, Lesarri Alberto, Cocinero Emilio J, Castaño Fernando
Department of Chemistry, University of Virginia, McCormick Rd, Charlottesville, VA 22904, USA.
Phys Chem Chem Phys. 2015 Jul 28;17(28):18282-7. doi: 10.1039/c5cp01025j.
We have examined the stereoselectivity of molecular recognition between two molecules of the anesthetic sevoflurane using broadband rotational spectroscopy. The transient axial chirality of sevoflurane is revealed upon the formation of the dimer, as two different diastereoisomers made of either homo- or heterochiral species are detected in a supersonic jet expansion. The conformational assignment was confirmed by the observation of eighteen different isotopologues in natural abundance (all possible (13)C's and two (18)O species of the homochiral form). The two clusters are formed in practically equal proportions (1.1 : 1), probably due to their similar hydrogen bonding topologies. In both clusters the complex is stabilized by a primary C-H···O hydrogen bond, assisted by weak C-HF interactions. This intermolecular binding regime is characterized by a mixture of electrostatic and dispersive interactions, midway between classical hydrogen bonds and van der Waals clusters.
我们利用宽带转动光谱研究了麻醉剂七氟醚两分子间分子识别的立体选择性。在二聚体形成时，七氟醚的瞬态轴向手性得以展现，因为在超声速喷射膨胀中检测到了由同手性或异手性物种构成的两种不同非对映异构体。通过观察天然丰度下的十八种不同同位素异构体（同手性形式的所有可能的¹³C以及两种¹⁸O物种），证实了构象归属。这两种簇以几乎相等的比例（1.1∶1）形成，可能是由于它们相似的氢键拓扑结构。在这两种簇中，复合物都通过主要的C-H···O氢键得以稳定，并伴有微弱的C-HF相互作用。这种分子间结合机制的特征是静电相互作用和色散相互作用的混合，处于经典氢键和范德华簇之间。
