Molar gibbs (free) energies of transfer of silver(I), copper(I) and potassium(I)

Abstract

Molar Gibbs energies of Ag+ for the transfer from acetonitrile into formamide, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, tetramethylurea, dimethyl sulphoxide, hexamethylphosphoric triamide, acetone, propylene carbonate, benzonitrile, N,N-dimethylthioformamide, N-methylthio-2-pyrrolidone and hexamethylthiophosphoric triamide have been calculated from the half-wave potentials of bis(biphenyl)chromium tetraphenylborate versus the silver, 0.01 mol dm–3 silver ion electrodes in the respective solvents as well as from polarographic half-wave potentials of Ag+vs. bis(biphenyl)chromium (I/O) in benzonitrile, N,N-dimethylthioformamide, N-methylthio-2-pyrrolidone and hexamethylthiophosphoric triamide. Molar Gibbs energies of transfer for K+ have also been calculated from polarographic half-wave potentials for the solvents mentioned, except for formamide and for hexamethylphosphoric triamide. Molar Gibbs energies of transfer for Cu+ from acetonitrile into benzonitrile, N,N-dimethylthioformamide, N-methylthio-2-pyrrolidone and hexamethylthiophosphoric triamide have been obtained from polarographic half-wave potentials employing the bis(biphenyl)chromium assumption. The data have been compared with molar Gibbs energies of transfer derived via the tetraphenylarsonium tetraphenylborate assumption and the assumption of negligible liquid junction potentials. A comparison of Gibbs energies of transfer for Ag+ with the data for K+ showed the difference in interactions between ‘hard’ and ‘soft’ solvents.