On the Electrochemical, Spectral and Photochemical Properties of Cyano-Nitrosyl Complexes. A Comparison between Iron and Ruthenium Analogues

Abstract

First order rate constant of cyanide splitting from one-electron product of the nitropruside 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 in CH3CN; E1/2 = -0.39 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 at the metal-to-nitrosyl charge transfer band.