Phosphate esters reacting with hydroxide

The bis-4-nitrophenylphosphate analogue [(NH3)5lrBNPP] reacts in a similar manner (79). The same rate law obtains and the rate constants are, ki = 4.8 X 10" L mol s and 2 = 1-2 x 10" L -mol" s at 25 °C. Despite the increased rate of production of the chelate phosphoramidate ester, it was still not observed by P NMR. Again, two products were observed by P NMR in constant ratio, independent of hydroxide concentration. They were the [(NH3)5lrNPP] ion and the complex 12, which reacted further by attack of the cis coordinated hydroxide ion on the phosphate ester. The [(NH3)5lrNPP]+ ion does not react further in the time scale of this experiment. This finding is in accord with our observations on the relative reactivity of the Co(III) and Ir(lII) complexes, which lead us to predict a half-life for hydrolysis of the [(NH3)5lrNPP] ion in IM NaOH at 25 °C of -200 h. 

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