| Authors | Hemayat Shekaari - Hamid Modarress |
|---|---|
| Journal | Amirkabir (Journal of Science and Technology) |
| Paper Type | Full Paper |
| Published At | 2003-8-23 |
| Journal Grade | ISI |
| Journal Type | Typographic |
| Journal Country | Iran, Islamic Republic Of |
Abstract
The formation constant for charge transfer complexes between electron acceptor (AgNO 3) and electron donor benzylcyanide (C 6H 5 - CH 2 - C ≡ N) in solvent ethyleneglycol [(CH 2OH) 2] has been evaluated by using the Nuclear Magnetic Resonance (NMR) chemical shifts of aromatic group of benzylcyanide measured against external referencres, tetrametylsilane (TMS),hexamethyldisilane (HMDS) and cylohexane (CXA) at 20°C. The external referencing procedure eliminated the interference of internal reference in the course of complexation. The necessary bulk magnetic susceptibility corrections on the measured chemical shifts have been made. The solution nonidealities and their effects on the formation constant have been considered and a new equation has been suggested to obtain the mean ionic activity coefficient of AgNO 3 from NMR results. The mean ionic activity coefficient has been taken into account in the formation constant calculations. The results indicated that the appropriate formation constant should be expressed in terms of activities. Also an equation have been derived to eliminate the undesirable effects on the NMR measured chemical shifts in calculating the formation constant. The selection of concentration domains and its effect on the calculated formation constant has been discussed and the new equation is modified to be independent of the concentration domains. In this equation the solution nonidealities, by considering the activity coefficients, have been taken into account.