Thermodynamics of interactions of Na+ ion with 15-crown-5 ether in the mixtures of water with dimethylsulfoxide at 298.15 K

Towards a Molecular Understanding of Cation‐Anion Interactions and Self‐aggregation of Adeninate Salts in DMSO by NMR and UV Spectroscopy and Crystallography

“…The change in enthalpy (ΔH=−23 kJ mol −1 ) for the 1 : 1 complexation between Na + and 15C5 ether is slightly larger than that previously reported in DMF [59] and DMSO [60] (ΔH=−20 and −15 kJ mol −1 , respectively) and is attributed to the use of anhydrous DMSO‐d 6 . The presence of water significantly reduces the binding of Na + to 15C5 ether.…”

The Ion Pair Thermal Model of MALDI MS

“…For AH + , in an exemplary case of A being diethyl ether, which is one of the weakest coordinating molecules, and M being CHCA, the concentration of AH + would be 2.4 × 10 -4 M assuming that the pKa of 3.5 in water for the conjugate acid of diethyl ether 43,44 and 1.17 in water for CHCA 27 can be used here, and the sample consists 10 pmol analyte in 25 nmol matrix. For A⁞Met + , in an exemplary case of A being 15-crown-5, Met + being Na + , and M being CHCA, the concentration of A⁞Met + would be 2.2 × 10 -5 M, which corresponds to a ratio of 7.3 × 10 -3 for A⁞Met + over A, assuming that the equilibrium constant 2.8 in water [45][46][47] can be used for equation (14), 1 µL typical LC-MS grade water with 0.2 ppm Na + is used to prepare the sample, and the sample consists 10 pmol analyte in 25 nmol CHCA (molar volume 133 mL/mol). Again, it is noted that the pKa values and equilibrium constant from the literature may be significantly different from the actual values in solid MALDI MS samples and estimations may be far away from being accurate.…”

Conductance and Thermodynamic Study of the Complexation of Ammonium Ion with Different Crown Ethers in Binary Nonaqueous Solvents

“…[4][5][6][7][8][9][10] However, the studies on the influence of solvent on formation of the crown ether-cation complexes are few, particularly in the mixed solvents. [1][2][3]11,12 Furthermore, crown ether-ammonium complexes are of fundamental interest as prototypical systems involving multiple hydrogen bonds. Study of these simple multiply-bound complexes is a promising means of gaining insight into much more complex macromolecular systems, such as those involved in protein folding or in the pairing of nucleo bases in polymetric nucleus acids.…”