Kinetics and the Redox Reaction between Bis (Aspatato) (Phenylamine) Cobalt (II) Dihydrate with Nitrite Ion in Aqueous Acidic Medium

                @article{CRSIJ26000346,
                  author = {Sulaiman Abdulkarim, Yusuf Abdulkarim, Yahaya Abdulkarim},
                  title = {Kinetics and the Redox Reaction between Bis (Aspatato) (Phenylamine) Cobalt (II) Dihydrate with Nitrite Ion in Aqueous Acidic Medium},
                  journal = {Cosmo Research and Science International Journal},
                  year = {2026},
                  volume = {2},
                  number = {2},
                  pages = {709-719},
                  issn = {3108-1584},
                  url = {https://cosmorsij.com/published/CRSIJ26000346.pdf},
                  abstract = {This research focused on the kinetic studies of the redox reaction between bis (aspatato) (phenylamine) Cobalt (II) dehydrate complex and nitrite ion in aqueous acidic medium under pseudo - first order condition in excess nitrite ion, temperature= 30°C+ 0.1°C, [H] = 0.15mol/dm3, lambda max=250nm.The study aimed to investigate stoichiometry, reaction order, rate dependence on acid concentration, dielectric constant and ionic strength, as well as to elucidate the mechanism of the reaction. Experimental results revealed that the redox process had a stoichiometric ratio of 1:6, indicating that one mole of nitrite ion reacted with six mole of cobalt (II) complex. The product analysis confirmed the formation of nitric oxide (NO) and Cobalt (III) ions as the major reaction product. Kinetic analysis showed that the reaction followed first order kinetic with respect to each reactant, yielding an overall second order rate law. The rate of the reaction was found to increase with decrease in dielectric constant of the medium and with increasing ionic strength, indicating that the reaction is acid dependent and influence by the surrounding ionic environment. Test for free radical participation and intermediate complex formation where both negative, suggesting the process proceed via the outer sphere electron transfer. On the basis of these observation, a direct electron transfer mechanism was proposed for the oxidation of bis (aspatato) (phenylamine) Cobalt (II) dehydrate by nitrite ion. The study recommends further investigation of the redox behaviour of the complex using other oxoanions to establish broader mechanistic trends, as well as the application of advanced spectroscopic techniques to characterize reaction intermediates and confirmed product formation. The reaction follows the rate equation below:Rate = (a+ b [H+]) [Co3+] [NO2-]},
                  keywords = {Aspartato, Phenylamine, Nitrite ion},
                  month = {September}
        }