Concerning the alleged efficiency of photoaquation in the ultraviolet photolysis of bromo(pentaammine)cobalt(III)

In order to complement and increase sensitivity in spectroscopic determination of small amounts of photolysis products in strongly adsorbing substrates, an ion-exchange method was to separate Co/sup 2 +/, Co(NH/sub 3/)/sub 5//sup 2 +/ and Co(NH/sub 3/)/sub 5/OH/sub 2//sup 3 +/. The results of this analysis reveal that the photolysis of Co(NH/sub 3/)/sub 5/Br/sup 2 +/ corresponds to a photoaquation yield of ca 0.025 +/- 0.01, indicating that earlier spectroscopic analysis result was not reliable. The data obtained are not in agreement with results obtained by Kirk et al who reported large quantum yields (0.15), for photoaquation following UV irradiation of this complex. The origin of this discrepancy is not clear. 11 references, 1 figure, 1 table.