O−H···O versus O−H···S Hydrogen Bonding I: Experimental and Computational Studies on the p-Cresol·H2O and p-Cresol·H2<

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• 作者：Himansu S. Biswal ; Pranav R. Shirhatti ; Sanjay Wategaonkar
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：May 14, 2009
• 年：2009
• 卷：113
• 期：19
• 页码：5633-5643
• 全文大小：319K
• 年卷期：v.113,no.19(May 14, 2009)
• ISSN：1520-5215

文摘

The weak hydrogen bonding ability of sulfur-containing hydrides makes it difficult to study their complexes and has not been characterized experimentally so far. In this work, the hydrogen-bonded complexes of H₂S and H₂O with p-cresol (p-CR) were studied using a variety of techniques such as two-color resonant two-photon ionization (2c-R2PI) spectroscopy, single vibronic level fluorescence (SVLF) spectroscopy, resonance ion dip infrared spectroscopy (RIDIRS), and fluorescence dip infrared spectroscopy (FDIRS), with an aim of comparing the nature and strength of their respective hydrogen bonding abilities. The intermolecular stretch (σ) and the shift in the O−H stretching frequency of p-CR in the complex were taken as the measures of the O−H···O and O−H···S hydrogen bonding strength. The experiments were complemented by the ab initio calculations, atoms in molecules (AIM), natural bond orbital (NBO), and energy decomposition analyses carried out at different levels of theory. The experimental data indicates that in the p-CR·H₂S complex, the phenolic OH group acts as a hydrogen bond donor, and sulfur as the acceptor. Further, it indicates that the p-CR·H₂S complex was about half as strong as the p-CR·H₂O complex. The AIM and NBO analyses corroborate the experimental findings. The energy decomposition analyses for the O−H···S hydrogen bond in the p-CR·H₂S complex reveal that the dispersion interaction energy has the largest contribution to the total interaction energy, which is significantly higher than that in the case of the p-CR·H₂O complex.