PHOTOCHEMISTRY OF COMPLEX IONS .8. PHOTOELECTRON PRODUCTION

An investigation of the photolytic production of hydrated electrons from aqueous solutions containing transition metal cyanide complexes and also IrCl63- is reported. A transient identified as due to eaq- has been observed in flash photolysis experiments with aqueous Fe(CN)64-, Mo(CN)84- W(CN)84-, and Ru(CN)64-. In addition, steady illumination experiments have been made using N2O as electron scavenger, to obtain the quantum yields φN2 (=φeaq-) for the above complexes and for IrCl63-. Values ranging from 0.031 to 0.66 are reported, using 254-mμ radiation. In the case of Mo(CN)84-, φN2 drops to essentially zero with irradiation at greater than 300 mμ. The results are interpreted as confirming previously suggested criteria for systems likely to show photoelectron production. The qualitative product analyses suggest, however, that in addition to the oxidized complex of the same stoichiometry as the starting material, there may also in some cases be produced a partly aquated species in the same or next higher oxidation state as that of the starting material.