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Protonation of benzo-18-crown-6: Extraction and DFT study
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SYSNO ASEP 0355840 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Protonation of benzo-18-crown-6: Extraction and DFT study Author(s) Toman, Petr (UMCH-V) RID, ORCID
Makrlík, E. (CZ)
Vaňura, P. (CZ)
Kašička, Václav (UOCHB-X) RID, ORCIDSource Title Zeitschrift für Physikalische Chemie : International Journal of Research in Physical Chemistry & Chemical Physics. - : Walter de Gruyter - ISSN 0942-9352
Roč. 225, č. 2 (2011), s. 265-270Number of pages 6 s. Language eng - English Country DE - Germany Keywords protonation ; nitrobenzene ; benzo-18-crown-6 Subject RIV CD - Macromolecular Chemistry R&D Projects GAP205/10/2280 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z40500505 - UMCH-V (2005-2011) AV0Z40550506 - UOCHB-X (2005-2011) UT WOS 000288686200007 DOI 10.1524/zpch.2011.0013 Annotation From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1•Na+(nb) reversible arrow 1•H3O+(nb) + Na+(aq) taking place in the two-phase water-nitrobenzene system (1 = benzo-18-crown-6, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(H3O+, 1•Na+)=-0.8±0.1. Further, the stability constant of the 1•H3O+ complex in water-saturated nitrobenzene was calculated for a temperature of 25°C as log βnb(1•H3O+)=6.3±0.1. Finally, by using quantum mechanical DFT calculations, the most probable structure of the 1•H3O+ cationic complex species was derived. In this complex, the hydroxonium ion H3O+ is bound by three strong linear hydrogen bonds to one (Ar–O–CH2) ethereal oxygen and two (CH2–O–CH2) ethereal oxygen atoms of the parent crown ligand 1. The interaction energy was found to be -401.4kJ/mol, confirming the formation of the considered complex 1•H3O+. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2011
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