Emmeluth Corinna, Poad Berwyck L J, Thompson Christopher D, Bieske Evan J
School of Chemistry, The University of Melbourne, Victoria, Australia 3010.
J Phys Chem A. 2007 Aug 9;111(31):7322-8. doi: 10.1021/jp070453r. Epub 2007 May 27.
The Cl- -C6H5CH3Ar, Cl- -C6H5NH2Ar, and Cl- -C6H5OH*Ar anion complexes are investigated using infrared photodissociation spectroscopy and ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that for Cl- -C6H5NH2 and Cl- -C6H5OH, the Cl- anion is attached to the substituent group by a single near-linear hydrogen bond. For Cl--C6H5CH3, the Cl- is attached to an ortho-hydrogen atom on the aromatic ring and to a hydrogen atom on the methyl group by a weaker hydrogen bond. The principal spectroscopic consequence of the hydrogen-bonding interaction in the three complexes is a red-shift and intensity increase for the CH, NH, and OH stretching modes. Complexities in the infrared spectra in the region of the hydrogen-bonded XH stretch band are associated with Fermi resonances between the hydrogen-stretching vibrational modes and bending overtone and combination levels. There are notable correlations between the vibrational red-shift, the elongation of the H-bonded XH group, and the proton affinity of the aromatic molecule's conjugate base.
使用红外光解离光谱和在MP2/aug-cc-pVDZ水平的从头算方法研究了Cl⁻-C₆H₅CH₃·Ar、Cl⁻-C₆H₅NH₂·Ar和Cl⁻-C₆H₅OH·Ar阴离子配合物。结果表明，对于Cl⁻-C₆H₅NH₂和Cl⁻-C₆H₅OH，Cl⁻阴离子通过单个近线性氢键连接到取代基上。对于Cl⁻-C₆H₅CH₃，Cl⁻通过较弱的氢键连接到芳环上的邻位氢原子和甲基上的一个氢原子上。三种配合物中氢键相互作用的主要光谱结果是CH、NH和OH伸缩模式的红移和强度增加。氢键XH伸缩带区域的红外光谱复杂性与氢伸缩振动模式与弯曲泛音和组合能级之间的费米共振有关。振动红移、氢键XH基团的伸长与芳族分子共轭碱的质子亲和力之间存在显著相关性。
