Thermodynamic studies of the solvation of Ph 4AsPh 4B in mixed solvents (MeOH—DMF)

Abstract

The thermodynamic data (Δ G 0, Δ H 0 and TΔ S 0) of the solvation of tetraphenylarsonium-tetraphenylborate (Ph 4AsPh 4B) and its neutral parts, tetraphenylgermanium (Ph 4Ge) and tetraphenylmethane (Ph 4C) in methanol— N,N-dimethylformamide mixed solvents are discussed. The values of the free energy of transfer, Δ s M G 0, are calculated from measurements of the solubilities of Ph 4AsPh 4B, Ph 4Ge and Ph 4C in the successive fractions of MeOH in DMF at three different temperatures (15, 25, 35°C). The values of Δ s M H 0 and TΔ s M S 0 for the derivatives are calculated from Δ s M G 0 values. The values of Δ s M G 0, Δ s M H 0 and TΔ s M S 0 of tetraphenylarsonium and tetraphenylborate ions have also been carefully calculated. The ratios of Δ s M G 0 values (Δ s M G 0 = Δ G 0(+)/Δ G 0(−)) were found to be greater than unity. Similarly, the ratios of Δ s M H 0 and TΔ s M S 0 for the positive and negative ions were found to be greater than unity.