Ion-Association and Solvation of Some Copper (I), Silver (I) and Tetraalkylammonium Salts in Binary Mixtures of Acetonitrile withn-Butyronitrile and N,N-Dimethylacetamide

Abstract

AbstractMolar conductances of Bu4NBPh4, Bu4NClO4, Bu4NI, Bu4NBr, Bu4NCF3COO, Pr4NBr, Et4NI, Et4NBPh4, NaClO4, NaBPh4, [Cu(CH3CN)4]ClO4and CF3COOAg have been measured in the concentration range (1–120) × 10−4mol dm−3in acetonitrile (AN) and binary mixtures of AN withn-butyronitrile (n-BTN) and DMA. The conductance data in all cases have been analyzed by the Shedlovsky method to evaluate ΛoandKAof these electrolytes. Some of these salts are associated in these solvent systems. Ion-association in case of silver (I) salts is the largest and relatively more in case of AN + DMA mixtures. Limiting ion conductances (λio) and hence actual solvated radii (ri) in all solvent systems have been evaluated using a modified form of Stoke's law. Cu+, Ag+and Na+are highly solvated, CF3COO−, ClO4−, Br−and I−are poorly/moderately solvated and tetraalkylammonium ions (R4N+) and Ph4B−are not solvated in AN +n-BTN and AN + DMA mixtures.