Abstract: | Abstract A simple sensitive and selective spectrophotometric method has been developed for determination of some transition metal ions. It is based on the reaction of the metal ions with excess peri-dihydroxynaphthindenone in 80% v/v ethyl alcohol-water mixture at 30°C. The colored products obtained display maximum absorption band at 560–590 nm depending upon the type of transition metal ion used, and E1 cm 1% in the range 70–480. Under the optimum conditions results with an average recovery of 96%, (mean standard deviation ±3% are obtained for 6 different transition metal ions without any significant interference from Li+, Na+, K+, Cs+, Rb+, Ba2+, Sr2+, Ni2+, Bi3+, Co2+, Mn+2, Cd+2 and Al+3. Kinetic data reveal that the reaction proceeds via a second order route (first order with respect to either the metal cation or ligand). The activation parameters and a suggested mechanism have been presented, and the nature of bonding in the solid chelate products has been verified. |