Pérez Cristóbal, López Juan C, Blanco Susana, Schnell Melanie
Max Planck Institute for the Structure and Dynamics of Matter , 22761 Hamburg, Germany.
The Hamburg Centre for Ultrafast Imaging at the Universität Hamburg , 22761 Hamburg, Germany.
J Phys Chem Lett. 2016 Oct 20;7(20):4053-4058. doi: 10.1021/acs.jpclett.6b01939. Epub 2016 Sep 30.
The complexes of 12-crown-4 ether (12C4) with water, generated in a supersonic jet, have been studied using broadband Fourier transform microwave spectroscopy. Three 1:1 and one 1:2 clusters have been observed and their structures unambiguously identified through the observation of isotopologue spectra. The structures of the clusters are based on networks of O-H···O and C-H···O hydrogen bonds. The most abundant 1:1 cluster is formed from the most stable S symmetry conformer of 12C4, even though it is not the energetically favored water complex. Interestingly, the structures of the most stable water cluster and the other remaining observed 1:1 and 1:2 complexes are formed from the second or the fifth most abundant conformers of 12C4. This shows the existence of a mechanism that changes the conformation of 12C4 so that the host-guest interactions can be maximized, even for a "soft" ligand like water.
利用宽带傅里叶变换微波光谱对在超声速射流中产生的12-冠-4醚（12C4）与水的配合物进行了研究。观测到了三个1:1和一个1:2的团簇，并通过观测同位素异构体光谱明确确定了它们的结构。这些团簇的结构基于O-H···O和C-H···O氢键网络。最丰富的1:1团簇由12C4最稳定的S对称构象体形成，尽管它不是能量上有利的水配合物。有趣的是，最稳定的水团簇以及其他观测到的1:1和1:2配合物的结构由12C4的第二或第五丰富的构象体形成。这表明存在一种机制，可改变12C4的构象，从而使主客体相互作用最大化，即使对于像水这样的“软”配体也是如此。
