| Abstract: | Aquation of cis-dinitrobisbiguaniderhodium (III) nitrate was investigated conductometrically. Rates of the release of first and the second nitro groups were derived by a graphical method. For both the steps of aquation, the presence of electron accepting ‘nitro’ group, favours ‘bond formation’ by the incoming ligand in the transition stage and it occurs before the ‘bond rupture’ is complete. The loss of the second ‘nitro’ group most probably takes place along with a hydrogen ion from the ‘aquo’ ligand introduced in the first step of aquation with the resultant formation of the hydroxoaquobisbiguanide complex. Activation parameters were evaluated and are as follows: ΔH? are 18±1.2 and 18.6±1.1 k cals mole?1 and ΔS? are ?15±2.7 and ?19±2.3 e. u. respectively for the first and the second steps of aquation. |
