Lobo Isabella A, Robertson Patrick A, Villani Luigi, Wilson David J D, Robertson Evan G
Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia.
J Phys Chem A. 2018 Sep 13;122(36):7171-7180. doi: 10.1021/acs.jpca.8b06649. Epub 2018 Aug 31.
Evidence and understanding of sulfur-centered hydrogen bonding, especially where the donor is a thiol, lags far behind that for conventional OH interactions. To help address this deficiency, conformer specific IR spectra of 2-phenylethanethiol (PET) and associated 1:1 solvent complexes have been measured in SH, OH, and CH stretch regions using resonant-two-photon-ionization (R2PI) and IR-UV ion dip spectroscopic techniques. The aromatic and aliphatic CH stretch regions show signature differences between anti and gauche conformers. Supported by ab initio calculations, a PET-water cluster with an OH···S arrangement and a PET-diethyl ether cluster expressing an SH···O interaction were identified. The SH stretch band of the SH···O complex is red-shifted and undergoes significant intensity enhancement compared to the bare molecule, which is characteristic of hydrogen bonding. These findings offer insight into the nature of the thiol functional group as a potential hydrogen bond donor and acceptor.
关于以硫为中心的氢键，尤其是供体为硫醇时的证据和理解，远远落后于传统的OH相互作用。为了弥补这一不足，使用共振双光子电离（R2PI）和红外-紫外离子偶极光谱技术，在SH、OH和CH伸缩区域测量了2-苯乙硫醇（PET）及其相关的1:1溶剂配合物的构象特异性红外光谱。芳香族和脂肪族CH伸缩区域显示出反式和顺式构象之间的特征差异。在从头算计算的支持下，鉴定出了具有OH···S排列的PET-水簇和表现出SH···O相互作用的PET-二乙醚簇。与裸分子相比，SH···O配合物的SH伸缩带发生红移且强度显著增强，这是氢键的特征。这些发现为硫醇官能团作为潜在氢键供体和受体的性质提供了深入了解。
