Wassermann Tobias N, Zielke Philipp, Lee Juhyon J, Cézard Christine, Suhm Martin A
Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany.
J Phys Chem A. 2007 Aug 9;111(31):7437-48. doi: 10.1021/jp071008z. Epub 2007 May 26.
n-Alkanols can occur in a multitude of energetically competitive conformational states. Using the OH stretching vibration as an infrared and Raman spectroscopic sensor in supersonic jet expansions, the torsional preferences around the Calpha-O and Cbeta-Calpha bonds are probed for n-propanol through n-hexanol. Raman detection is more powerful for isolated monomers, whereas IR spectroscopy is more sensitive for molecular complexes. The subtle IR vibrational shift induced by the nanocoating of n-alcohols with Ar atoms is shown to alternate with chain length. A large number of alcohol dimer absorptions is observed and subjected to collisional relaxation and nanocoating conditions. Essential features of the dimer spectra are modeled successfully by a simple force field approach. Exploratory quantum chemical calculations up to the MP2/aug-cc-pvqz level encourage a rigorous theoretical study of the subtle conformational aspects in monomers and possibly also in dimers of linear alcohols.
正链烷醇可以以多种能量竞争的构象状态存在。在超声速射流膨胀中，使用OH伸缩振动作为红外和拉曼光谱传感器，对正丙醇到正己醇围绕Cα-O和Cβ-Cα键的扭转偏好进行了探测。拉曼检测对于孤立的单体更有效，而红外光谱对分子复合物更敏感。结果表明，用Ar原子对正链烷醇进行纳米包覆所引起的微妙红外振动位移会随链长而交替变化。观察到大量醇二聚体吸收，并对其进行了碰撞弛豫和纳米包覆条件的研究。通过简单的力场方法成功地模拟了二聚体光谱的基本特征。高达MP2/aug-cc-pvqz水平的探索性量子化学计算鼓励对线性醇单体以及可能的二聚体中微妙的构象方面进行严格的理论研究。
