ON THE ELECTROCHEMICAL, SPECTRAL AND PHOTOCHEMICAL PROPERTIES OF CYANONITROSYL COMPLEXES - A COMPARISON BETWEEN IRON AND RUTHENIUM ANALOGS

First order rate constant of cyanide splitting from one-electron product of the nitroprusside ion reduction was determined using a.c. polarography (k = 350 s-1 in CH3CN). [Ru(CN)5(NO)]2- ion is reduced reversibly (E1/2 = -1.04 V, k0 = 4.86 . 10(-3) m s-1 iri CH3CN; E1/2 = -0.3 V in H2O) with one electron. IR and EPR study indicates dimerization of the reduction product in solution but no cyanide splitting from electrogenerated [Ru(CN)5(NO)]3- was detected. Further reduction of [Ru(CN)5(NO)]3-, with consumption of protons. occurs in aqueous media. Efficient photochemical reactions of [Fe(CN)4(NO)]2- with O2. KMnO4 and pyridine take place when the complex is excited ai the metal-to-nitrosyl charge transfer band.