A Study of lon-dipole Interaction Energy of Some Common and Tetraalkylammonium Ions in Different Solvents

B. S. N. V. Degree College, Lucknow

Manuscript received 3 July 1975 ; revised 10 January 1976 ; accepted 19 February 1976.

Ion-dipole interaction energy, ∆E_ID, of some cations and anions in five solvents namely H₂O, DMA, DMSO, EC and PC** and dipole-dipole interaction energy, ∆E_DD of these five solvents have been calculated. The ratio ∆E_ID/∆E_DD has also been calculated for the R₄N⁺ ions in these solvents. The calculated values of ion-dipole interaction energy have been found to be exception ally high for the common and compact cations like Li+, Na +, etc. and appreciably high for the anions like F^-,Cl^-,Br^- etc., whereas in case of tetraalkylammonium ions (R₄N⁺), these values have been found to be quite low but slightly greater than the corresponding dipolar interaction energy of the solvents except in H₂O for larger R₄N⁺ ions. The dipole-dipole interaction energy value decreases with increasing size of the solvent molecule. The ratio ∆E_ID/∆E_DD has been found to be greater than unity in all cases except for larger R₄N⁺ ions in water which appear to be solvated, specially the smaller ones in EC, PC, DMSO and DMA ; however in case of water only (CH₃)₄N⁺ and (C₂H₅)₄N⁺ ions are supposed to bo solvated. Solvation of ion has been found to be directly related to the dielectric constant of the medium.