Characterization of Highly Unusual NH+鈥揙 Hydrogen Bonding to Ester Ether Oxygen Atoms through Spectroscopic and Computational Studies

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• 作者：Michael T. Scerba ; Andrew F. DeBlase ; Steven Bloom ; Travis Dudding ; Mark A. Johnson ; Thomas Lectka
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：April 12, 2012
• 年：2012
• 卷：116
• 期：14
• 页码：3556-3560
• 全文大小：278K
• 年卷期：v.116,no.14(April 12, 2012)
• ISSN：1520-5215

文摘

We characterize a highly unusual, charged NH鈥揙 hydrogen bond formed within esters of 8-(dimethylamino)naphthalen-1-ol in which an ammonium ion serves as an intramolecular hydrogen bond donor to spatially proximate ester ether oxygen atoms. Infrared spectroscopic analysis of the ester carbonyl frequencies demonstrates significant blue-shifting when ether hydrogen bonding is possible, in stark contrast to the more commonly observed red shift that occurs upon hydrogen bonding to the ester carbonyl oxygen. The intrinsic behavior of the linkage (i.e., in which counterions and solvent effects are eliminated) is provided by vibrational predissociation spectroscopy of the isolated gas-phase cations complexed with weakly bound D₂ molecules.