Acta Phys. -Chim. Sin. ›› 1985, Vol. 1 ›› Issue (02): 109-110.doi: 10.3866/PKU.WHXB19850201

• Communication •     Next Articles

A STUDY ON THE SOLVATION OF Na+ IN BINARY MIXTURE OF SOLVENTS BY Na+-23 NMR

Huang Yining; Li Zhifen; Liu Ruilin   

  1. Institute of Physical Chemistry; Peking University
  • Received:1984-12-17 Revised:1985-01-22 Published:1985-04-15

Abstract: ~(23)Na~+ chemical shift of NaClO_4 in mixed solvents of water-aceton,water-ace- tonitrile, and water-ethanol and of NaBPh_4 in methanol-DMF,methanol-ben- zene, and methanol-dioxane were measured.By means of iso-solvation point the solvating abilities were compared as water>aceton≥acetonitrile≥ethanol and DMF>methanol. The preferential solvation free energies of Na~+ for the pairs of solvents, methanol-DMFand water-aceton,were evaluated as -2.7 kJ mol~(-1) for DMF to methanol and 4.6 kJ mol~(-1) for aceton to water.
~(23)Na~+ chemical shift in methanol-benzene is independent of the content of benzene. It verifies the simple solvation modle for ion in methanol-inert solvent mixture. However the chemical shift of ~(23)Na~+ in methanol-dioxane mixture varies with the composition of solvent. The inewidth of Na-23 resonance peak increases dramtically with the increasing of dioxane. It seems that the dioxane molecules disturb the primary solvation shell of Na~+ in methanol and result a unsymmetrical immediate surrounding for Na~+ cation.