RADIOLYSIS OF BINARY AND MIXED-LIGAND PALLADIUM(II) COMPLEXES WITH 2,2-BIPYRIDINE AND 1-AMINO-ACID LIGANDS

Steady state and pulse radiolysis studies on binary and ternary pallad ium(II) complexes of the type [Pd(1-aa)(2)] and [Pd(bipy)(1-aa)](+) wh ere, 1-aa = 1-valinate (valO), 1-leucinate (leuO), 1-isoleucinate (iso leuO) and bipy = 2,2'-bipyridine have been carried out in aqueous medi um. The ternary complexes show a negligible loss of optical activity w ith e(aq)(-) while, with (OH)-O-. a significant loss of optical activi ty is observed with the formation of a new optically active species at high gamma-dose. The site of attack of both the primary radiolytic sp ecies in these ternary complexes is inferred to be the bipy ring. The binary complexes, on the contrary, show a substantial loss of optical activity with both e(aq)(-) and (OH)-O-.. Formation of fine metal pall adium particles is observed with e(aq)(-) while, with (OH)-O-. a new o ptically active species is formed as confirmed from CD results. The si te of attack of both e(aq)(-) and (OH)-O-. is inferred to be the palla dium(II) centre in these binary complexes. The G(-complex) values have been estimated from CD results. The kinetic parameters and absorption characteristics of the transient species formed in the reaction of e( aq)(-) and (OH)-O-. with all these complexes have been determined usin g the pulse radiolysis technique.