ION-SOLVENT INTERACTION - EFFECTS OF ADDED POLAR COMPOUNDS ON THE CONDUCTANCES OF SEVERAL ALKALI-METAL SALTS IN 2-BUTANONE AT 25-DEGREES-C

The conductance parameters, A0 and for lithium picrate, sodium picrate, tri-n-butylammonium picrate, and lithium tetraphenylborate have been evaluated from the conductances measured as a function of salt concentration in solvent mixtures of 2-butanone with small amounts (up to 0.01 M) of added hexamethylphosphoric triamide (HMPA), triphenylphosphine oxide (TPPO), dimethyl sulfoxide (Me2xSO), trisethanolamine (TEA), and glyme-5. Values of cation-ligand association constants, K1+, derived from the changes in limiting molar conductances, A0, are shown to be the same as those derived from changes in ion pair association constants, KA, in the cases of lithium picrate and lithium tetraphenylborate with the ligands HMPA and TPPO. The magnitudes of Ki+are listed in parentheses after each ligand in the order with lithium (all ligands), with sodium (HMPA, TPPO, and TEA) and with tri-n-butylammonium (HMPA and TPPO only) cations for HMPA (1500, 37, 220), for TPPO (250, 18, 56), for TEA (6000, 110), for Me2SO (12), and for glyme-5 (~0). It is found that, with the exception of glyme-5, there is only a small effect of changing solvent on the exchange of one ligand for another in the complex with lithium cation. © 1979, American Chemical Society. All rights reserved.