The structure and vibrational features of proton disolvates in water–ethanol solutions of HCl: the combined spectroscopic and theoretical study |
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| Authors: | Vladimir D Maiorov Irina S Kislina Alexey A Rykounov Mikhail V Vener |
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| Institution: | 1. Semenov Institute of Chemical Physics, Russian Academy of Sciences, , Moscow, Russia;2. Snezhinsk Physics and Technology Institute, National Research Nuclear University MEPhI, , Snezhinsk, Russia;3. Quantum Chemistry Department, Mendeleev University of Chemical Technology, , Moscow, Russia |
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| Abstract: | The infrared (IR) spectra of water–ethanol (EtOH) solutions of HCl are measured over a wide range of acid concentration at fixed H2O―EtOH ratios (1 : 1, 1 : 2, and 1 : 40). In these systems, different proton disolvates with (quasi)symmetrical H‐bonds are formed. Their structure and vibrational features are revealed by the density functional theory method coupled with the polarizable continuum model of solvation. In dilute acidic solutions, the Zundel‐type H5O2+ ion is mainly formed. In concentrated HCl solutions, the ions (H2O···H···O(H)Et)+ and (Et(H)O···H···O(H)Et)+ with the quasi‐symmetrical O···H+···O unit having O···O separation <2.45 Å appear. The first ion characterized by the IR‐intensive band around 1800 cm?1 is mainly formed in the 1 : 1 water–ethanol systems. The second ion exists in the 1 : 2 and 1 : 40 water–ethanol systems. Its spectroscopic signatures are the groups of the IR‐intensive bands around 800 and 1050 cm?1. In highly concentrated HCl solutions with the 1 : 40 water–ethanol ratio, a neutral Et(H)O···H+···Cl? complex exists. Copyright © 2013 John Wiley & Sons, Ltd. |
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| Keywords: | DFT computations multiple frustrated total internal reflection IR spectroscopy short (quasi)symmetrical H‐bonds the continuous absorption the polarizable continuum model |
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