Complex formation of monovalent cations with biofunctional ligands

Solvent dependence of the stability of cryptate complexes

“…The majority of studies concerned with equilibria of complex formation between naturally occurring or synthetic macrocyclic ligands and cations (particularly alkali or alkaline earth cations) have involved water or methanol as solvent1 and refer to a single-solvent reaction as in eq 1. Such studies have shown that M"+(aq) + L(aq) -ML"+(aq) (1) many of the ligands show considerable selectivity in complex formation. However, both the overall stabilities of the complexes and the selectivity patterns of the ligands might be expected to be solvent dependent.…”

Measurement of gas‐phase binding energies of crown ethers with metal ions by Fourier‐transform ion cyclotron resonance mass spectrometry

“…The various methods for the determination of complexation constants of crown ethers have been reviewed. [1][2][3] Recently, one of us has demonstrated the use of 252Cf plasma desorption mass spectrometry for the semi-quantitative study of the relative complexation of alkali metal ions with crown ether^.^ Fast-atom bombardment mass spectrometry (FAB-MS) has also been used to determine crown ether-alkali cation stability constant^.^ Pulsed laser desorption of involatile species for subsequent mass spectrometric analysis has been quite successful in recent years,6 particularly in conjunction with Fourier-transform ion cyclotron resonance (FTICR) mass ~pectrometry.~-'' Recent reports from our laboratory have illustrated the use of laserdesorption mass spectrometry (LD-MS) to study the collisionally-activated dissociation (CAD) of pyridinium including measurement of their dissociation energies. The binding energiedaffinities of the crown ethers for different alkali metal cations are known to be strongly solvent and counterion dependent.…”

Kinetics of formation and dissociation of the cryptates silver(2,2,2)+ and potassium(2,2,2)+ in acetonitrile + water mixtures at 25.degree.C

“…The Gibbs free energy of the transition state, AG* (M+™(2,2,2),C104~), at mole fraction x^depends upon the Gibbs free energies of transfer of the reactants, MC104 and (2.2.2) , and the free energies of activation of the formation reaction (eq 4). AGf*(xAN) may be obtained from the AG'(M+...(2,2,2),C1041 = AGtr(MC104) + AGtr(2,2,2) + AGf*(xAN) (4) formation rate fef(xAN) by using eq 5, in which kB is…”