Protonation of Benzo-18-crown-6: Extraction and DFT Study
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Petr Toman
Abstract
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1·Na+(nb)⇌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+.
© by Oldenbourg Wissenschaftsverlag, Pilsen, Germany
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Artikel in diesem Heft
- Kinetic Analysis of High-Rate and of Low-Rate Regimes in CO Oxidation on Pt Group Metals: Evidence for Vibrational Excitation of the O-Rich Adlayer and for Thermal Equilibrium of the CO-Rich Phase
- Effect of Particle Size on Non-Isothermal Decomposition of Potassium Titanium Oxalate
- Inelastic Neutron Scattering (INS) Study of Low Frequency Vibrations and Hydrogen Bonding of (E)-2-Hydroxyimino-2-Cyanoacetic Acid Ethyl Ester
- Electrochemical and in situ Spectroelectrochemical Properties of Phthalocyanines Bearing N-Benzyl-4-Phenyloxyacetamide Moieties
- Initial State and Transition State Contributions to Reactivity Trends of Base-Catalyzed Hydrolysis of Some Nitro Chromen-2-One Derivatives
- Studies on the Kinetics of Tetraethylammonium Bromochromate Oxidation of Some Meta- and Para-Substituted Benzyl Alcohols in Non-Aqueous Media
- Protonation of Benzo-18-crown-6: Extraction and DFT Study
- Contribution to the Complexation of some Univalent Metal Cations with p-Tert-Butylcalix[4]arene-Tetrakis(N,N-Diethylacetamide) in Nitrobenzene Saturated with Water
