STEADY-STATE AND PULSE-RADIOLYSIS OF SOME PALLADIUM(II) COMPLEXES

Steady-state and pulse radiolysis studies of three complementary palla dium(II) complexes, [Pd(bipy)Cl2]. [Pd(bipy)(HypO)]Cl and [Pd(HypO)2] (bipy = 2,2'-bipyridine, HypO = 4-hydroxy-L-prolinate) have been perfo rmed. The site of attack of e-(aq) and OH. radical in these complexes and the effect of gamma irradiation on the optical activity of the com plexes containing HypO has been assessed using optical absorption and circular dichroism techniques. The steady-state gamma irradiation resu lts for [Pd(bipy)Cl2] and [Pd(bipy)(HypO)]+ are significantly differen t from those of [Pd(HypO)2] with both e-(aq) and OH.. Precipitation of fine metal palladium particles is observed in the reaction of e-(aq) with [Pd(HypO)2]. Formation of a new optically active species is obser ved in the reaction of OH. with both [Pd(HypO)2] and [Pd(bipy) (HypO)] + accompanied by a substantial loss in optical activity of the parent complexes. The substitution of one amino acid ligand in [Pd(HypO)2] wi th bipy leads to a change in the site of attack of e-(aq) from the met al centre in the binary complex to the bipy ring in the ternary comple x. The pulse-radiolysis results support inferences drawn from the stea dy-state gamma-radiolysis investigations.