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Pregled bibliografske jedinice broj: 447653

Časopis

Autori: Požar, Josip; Preočanin, Tajana; Frkanec, Leo; Tomišić, Vladislav
Naslov: Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative
( Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative )
Izvornik: Journal of solution chemistry (0095-9782) 39 (2010); 835-848
Vrsta rada: članak
Ključne riječi: Calixarenes; Complexation; Microcalorimetry; Thermodynamics; Solvation; Hydrogen bonds
( Calixarenes; Complexation; Microcalorimetry; Thermodynamics; Solvation; Hydrogen bonds )
Sažetak:
Complexation of alkali metal cations with 5, 11, 17, 23-tetra-tert-butyl-26, 28, 25, 27-tetrakis(O-methylD-α-phenylglycylcarbonylmethoxy)calix[4]arene (L) in methanol and acetonitrile was studied by means of direct and competitive microcalorimetric titrations at 25 °C. The thermodynamic parameters of complexation reactions showed that all the reactions investigated were enthalpically controlled. In both solvents the reaction enthalpy was most favourable for Na+ binding with L leading to the highest affinity of the examined calix[4]arene derivative towards this cation. The Solubilities (and consequently the solution Gibbs energies) of the ligand were determined, as were the corresponding solution enthalpies and entropies. No significant difference between the solution thermodynamic quantities of L in the two solvents was observed, whereas the transfer of complex species from methanol to acetonitrile was found to be quite favourable. The interactions of solvent molecules with the free and the complexed ligand were investigated by 1H NMR spectroscopy. It was concluded that in both cases an inclusion of an acetonitrile molecule into the hydrophobic cavity of L occurred, which significantly affected the cation complexation in this solvent. The thermodynamic data were discussed regarding the structural properties of the ligand, the free and the complexed cations as well as the solvation abilities of the solvents examined. In this respect, the specific solvent-solute interactions and the intramolecular NH•••O=C hydrogen bonds at the lower rim of L were particularly addressed.
Projekt / tema: 119-1191342-2960, 119-1191342-2961, 098-0982904-2912
Izvorni jezik: eng
Rad je indeksiran u
bazama podataka:
Current Contents Connect (CCC)
Scopus
SCI-EXP, SSCI i/ili A&HCI
Science Citation Index Expanded (SCI-EXP) (sastavni dio Web of Science Core Collectiona)
Kategorija: Znanstveni
Znanstvena područja:
Kemija
URL Internet adrese: http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s10953-010-9550-9
URL cjelovitog teksta:
Google Scholar: Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative
Upisao u CROSBI: vtomisic@chempmf.hr (vtomisic@chempmf.hr), 12. Ožu. 2010. u 09:03 sati



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