SYNTHESIS, CHARACTERIZATION AND REACTIVITY OF THE PROPIONITRILE COMPLEXES OF RUTHENIUM(II) AND RUTHENIUM(III)

The complexes [Ru(NH3)5(NCC2H5)](PF6)n (n = 2, 3) have been isolated a nd characterized by microanalysis, cyclic voltammetry, UV-vis and IR s pectroscopies. in acidic media, C(H+) = 1 x 10(-3) M, mu = 0.10 M (NaC F3COO) at (25.0 +/- 0.1)-degrees-C, the complex ion [Ru(NH3)5(NCC2H5)] 2+ undergoes aquation yielding the trans-[Ru(NH3)4(NCC2 H5)(H2O)]2+ io n, with k(-NH3) equal to (1.2 +/- 0.1) x 10(-5) s-1. The specific rate s k1, k-1 and K(eq) for the reaction: [GRAPHICS] are, respectively, 8. 6 x 10(-3) M-1 s-1, 1.6 x 10(-5) s-1 and 5.4 x 10(2) M-1, under the sa me experimental conditions described above. The value for the pK(a) of the acid trans-[Ru(NH3)4(NCC2H5)(pzH)]3+ was calculated as (1.6 +/- 0 .1), mu = 0.1 M (NaCF3COO) at (25.0 +/- 0.1)-degrees-C. The complex io n [Ru(NH3)5(NCC2H5)]3+ undergoes hydrolysis in alkaline medium yieldin g the propanamide complex of pentaammineruthenium(III), with k(OH) equ al to (1.9 +/- 0.1) x 10(2) M-1 s-1.