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Pregled bibliografske jedinice broj: 447653

Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative


Požar, Josip; Preočanin, Tajana; Frkanec, Leo; Tomišić, Vladislav
Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative // Journal of solution chemistry, 39 (2010), 835-848 (međunarodna recenzija, članak, znanstveni)


Naslov
Thermodynamics of Complexation of Alkali Metal Cations by a Lower-Rim Calix[4]arene Amino Acid Derivative

Autori
Požar, Josip ; Preočanin, Tajana ; Frkanec, Leo ; Tomišić, Vladislav

Izvornik
Journal of solution chemistry (0095-9782) 39 (2010); 835-848

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
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.

Izvorni jezik
Engleski

Znanstvena područja
Kemija



POVEZANOST RADA


Projekt / tema
098-0982904-2912 - Samo-udruživanje u gelovima i sinteza funkcionalnih hibridnih materijala (Leo Frkanec, )
119-1191342-2960 - Elektroliti i koordinacijske reakcije u otopini (Vladislav Tomišić, )
119-1191342-2961 - Fizikalna kemija koloida i međupovršina (Nikola Kallay, )

Ustanove
Institut "Ruđer Bošković", Zagreb,
Prirodoslovno-matematički fakultet, Zagreb

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus