COPPER(III) PYROPHOSPHATE COMPLEXES IN AQUEOUS-SOLUTION - A PULSE-RADIOLYSIS STUDY AT AMBIENT AND HIGH-PRESSURE

The reaction between OH radicals and [CUII(P2O7)(2)(H2O)(2)](6-) resul ts in the formation of a Cu(III) complex. No reaction is observed with N-3(.) or Br-2(.-), whereas SO4.- initiates the same steps as seen wi th (OH)-O-.. This suggests that the mechanism probably involves a liga nd interchange or H atom abstraction process. The Cu(III) complex unde rgoes a rapid first-order reaction, probably loss of a P2O74- chelate, followed by addition of OH- (pK(OH) approximate to 10) to yield a Cu( III) complex that is predominantly hydroxylated and has a relatively l ong half life. The effect of pressure (up to 150 MPa) on the formation and subsequent reactions of the Cu(III) complex is used to help eluci date the mechanism of the different steps.