A Partial Proton Transfer in Hydrogen Bond O鈭?/b>H路路路O in Crystals of Anhydrous Potassium and Rubidium Complex Chloranilates

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• 作者：Nikola Bilis虒kov ; Biserka Kojic虂-Prodic虂 ; Gregor Mali ; Kres虒imir Molc虒anov ; Jernej Stare
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：April 14, 2011
• 年：2011
• 卷：115
• 期：14
• 页码：3154-3166
• 全文大小：1108K
• 年卷期：v.115,no.14(April 14, 2011)
• ISSN：1520-5215

文摘

Hydrogen bonding and proton transfer in the solid state are studied on the crystals of isostructural anhydrous potassium and rubidium complex chloranilates by variable-temperature single crystal X-ray diffraction, solid state ¹H NMR and IR spectroscopies, and periodic DFT calculations of equilibrium geometries, proton potentials, and NMR chemical shifts. Their crystal structures reveal neutral molecules of chloranilic acid and its dianions connected into a chain by O鈭扝路路路O hydrogen bond. A strong hydrogen bond with a large-amplitude movement of the proton with NMR shift of 13鈭?7 ppm and a broad continuum in IR spectra between 1000 and 500 cm^鈭? were observed. Periodic DFT calculations suggest that proton transfer is energetically more favorable if it occurs within a single pair of chloranilate dianion and chloranilic acid molecule but not continuously along the chains of long periodicity. The calculated chemical shifts confirm the assumption that the weak resonance signals observed at lower magnetic fields pertain to the case when the proton migrates to the acceptor side of the hydrogen bond. The detected situation can be described by a partial proton transfer.