Solvent effect on complexation of alkali-metal cations by a calix[4]arene amide derivative (CROSBI ID 607183)
Prilog sa skupa u zborniku | sažetak izlaganja sa skupa | međunarodna recenzija
Podaci o odgovornosti
Horvat, Gordan ; Stilinović, Vladimir ; Kaitner, Branko ; Frkanec, Leo ; Tomišić, Vladislav
engleski
Solvent effect on complexation of alkali-metal cations by a calix[4]arene amide derivative
Complexation of alkali-metal cations by a lower- rim calix[4]arene secondary-amide derivative (L) in benzonitrile (PhCN) and methanol (MeOH) was studied at 25 °C by means of microcalorimetry, UV and 1H NMR spectroscopies, and single-crystal X- ray diffraction. Classical molecular dynamics simulations (MD) of the systems studied were carried out as well. The results of these investigations were compared with those obtained previously for acetonitrile (MeCN) as a solvent. The stability constants of 1:1 ML+ complexes were determined (the values obtained by different methods being in excellent agreement), as were the corresponding complexation enthalpies and entropies. Both enthalpic and entropic contributions were found to be favourable for the reactions examined. However, thermodynamic stabilities of the ML+ complexes were quite solvent dependent (stability decreased in the solvent order: MeCN > PhCN > MeOH), which could be accounted for by considering the differences in the solvation of the ligand as well as free and complexed alkali-metal cations in the solvents used. Interestingly, macrocycle L was proven to be a better binder of Li+ compared to Na+ in PhCN, which was in contrast to MeCN as a solvent. That could be explained by the inclusion of a PhCN molecule into the ligand hydrophobic cone of the LiL+ complex observed in the solid state. More precisely, in the molecular structure of the lithium complex of L determined by the X-ray diffraction analysis, the PhCN molecule bound in the calixarene basket was found to coordinate the Li+ cation by its nitrile group, which is energetically quite favourable. The experimental results were supported by those obtained by MD simulations.
calixarene ; alkali-metal cations ; complexation ; thermodynamics ; solvation
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Podaci o prilogu
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2013.
objavljeno
Podaci o matičnoj publikaciji
Podaci o skupu
44th World Chemistry Congress
predavanje
11.08.2013-16.08.2013
Istanbul, Turska