SUBSTITUTION-REACTIONS OF RUTHENIUM(II) COMPLEXES CONTAINING HETEROCYCLIC LIGANDS - AQUATION OF BIS-BIPYRIDINE-DI(1,2,4-TRIAZOLE)RUTHENIM(II) IN PERCHLORIC-ACID

Aquation of [Ru(bipy)2(Htrz)2]2+, (where Htrz = 1, 2, 4-triazole, a he terocyclic ligand) in the presence of perchloric acid (0.05-1.0 mol dm -3) has been investigated spectrophotometrically between 21-degrees to 40-degrees-C. The reaction proceeds in stages with the formation of m onoaqua and diaqua products which subsequently undergoes a redox react ion to give ruthenium(III) and other products. Activation parameters a re: DELTAH# 64 +/- 4, 64 +/- 3 and 73 +/- 4 kJ mol-1 and DELTAS# - 94 +/- 8, -102 +/- 8 and -76 +/- 10 JK-1 mol-1 respectively for the first step and acid-free and acid-catalysed paths of triazole complex is mo re inert due to its higher enthalpy of reaction and bonding properties . Aquation of the complex shows appreciable associative character.