ABSTRACT
Conductance measurements of an electrolyte solution in the presence of a crown compound provide two valuable pieces of information. The useful piece of information relates to the transport phenomena of the crown compound-electrolyte complex in the solution. Analyses of the transport data yield the mobility of the crown compound-cation complex, the ion-pair dissociation constant of the crown compound-electrolyte complex, and the distance of closest approach of this ion pair. Stability constants of crown compound-cation complexes have been determined by various methods, such as potentiometry, polarography, Nuclear magnetic resonance (NMR), calorimetry, and solubility. Structures of crown compound-cation complexes in solutions are estimated from the above three conductance parameters as well as complex formation constants. In order to obtain highly cation-selective reagents, numerous crown compounds have been synthesized; their cation-complexing abilities and cation selectivities have been studied by various methods.
