HYDROLYSIS OF ORTHOPHOSPHATE, PYROPHOSPHATE, AND TRIPHOSPHATE COORDINATED TO BIS(ETHYLENEDIAMINE)COBALT(III)

The hydrolysis of bidentate ortho-, pyro-, and triphosphates in bis(et hylenediamine)cobalt(III) complexes have been carried out in HClO4, HC l, HNO3 and monochloroacetic acid at 30 degrees C by estimating the re lease of free phosphate. A pseudo-first order rate behaviour has been found under experimental conditions. The rate constants for the hydrol ysis in 1 M HClO4 has been found to be 0.16 x 10(-3), 0.30 x 10(-3) an d 0.96 x 10(-3) min(-1), for the ortho-, pyro- and triphoshate complex es, respectively. The rate of hydrolysis decreases in metal-phosphato complexes compared to that in the respective adducts and condensed pho sphates. The rate of hydrolysis for the complexes decreaess along the series triphosphate > pyrophosphate > orthophosphate.