Single Hydration of the Peptide Bond: The Case of the Vince Lactam

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• 作者：Patricia 脡cija ; Francisco J. Basterretxea ; Alberto Lesarri ; Judith Mill谩n ; Fernando Casta帽o ; Emilio J. Cocinero
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：October 18, 2012
• 年：2012
• 卷：116
• 期：41
• 页码：10099-10106
• 全文大小：430K
• 年卷期：v.116,no.41(October 18, 2012)
• ISSN：1520-5215

文摘

2-Azabicyclo[2.2.1]hept-5-en-3-one (ABH or Vince lactam) and its monohydrated complex (ABH路路路H₂O) have been observed in a supersonic jet by Fourier transform microwave spectroscopy. ABH is broadly used in the synthesis of therapeutic drugs, whereas the ABH路路路H₂O system offers a simple model to explain the conformational preferences of water linked to a constrained peptidic bond. A single predominant form of the Vince lactam and its singly hydrated complex have been detected, determining the rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling tensor. The monohydrated complex is stabilized by two hydrogen bonds (C鈺怬路路路H鈥揙 and N鈥揌路路路O) closing a six-membered ring. The complexation energy has been estimated to be 10 kJ mol^鈥? from experimental results. In addition, the observed structure in the gas phase has been compared with solid-phase diffraction data. The structural parameters and binding energies of ABH路路路H₂O have also been compared with similar molecules containing peptide bonds. Ab initio (MP2) and density functional (M06-2X and B3LYP) methods have supported the experimental work, describing the rotational parameters and conformational landscape of the title compound and its singly hydrated complex.