KINETICS AND MECHANISM OF REACTIONS OF THE ETHYLENEBIS(BIGUANIDE) SILVER(III) ION IN AQUEOUS PERCHLORATE-MEDIA

Kinetics of oxidation of eleven organic and inorganic substrates by the ethylenebis(biguanide)silver(III) ion have been determined in aqueous perchlorate media. Widely different rates and mechanistic versatility were observed thereby. Depending on the nature of the reductant, inner sphere, outer sphere, or Ag+-catalysed reactions may be observed. The Ag+-catalysis may involve a Ag+/Ag0 or Ag(I)/Ag(II) catalytic cycle. Factors controlling the nature of the mechanistic pathways to be adopted, have been discussed. The Ag(III) complex is kinetically more active than its conjugate bases towards a neutral or anionic reductant. Towards a cationic reductant, however, the conjugate bases are more active. This complex exhibits some kinetic selectivity in its reactions and could therefore be utilised in kinetic methods for estimation of benzyl alcohol and hypophosphite.