Time-resolved infrared (TRIR) flash photolytic techniques have been employed to initiate and observe the efficient dissociation of CO from a synthetic heme-CO/copper complex, [(L-6)Fe-II(CO)center dot center dot CuI](+) (2), in CH3CN and acetone at room temperature. In CH3CN, a significant fraction of the photodissociated CO molecules transiently bind to copper (v(CO)(Cu) = 2091 cm(-1)) giving [(6L)Fe(II)center dot center dot Cu-I(CO)](+) (4), with an observed rate constant, k(1) = 1.5 x 10(5) s(-1). That is followed by a slower direct transfer of CO from the copper moiety back to the heme (v(CO)(Fe) = 1975 cm(-1)) with k(2) = 1600 s(-1). Additional transient absorption (TA) UV-vis spectroscopic experiments have been performed monitoring the CO-transfer reaction by following the Soret band. Eyring analysis of the temperature-dependent data yields Delta H-dagger = 43.9 kJ mol(-1) for the 4-to-2 transformation, similar to that for CO dissociation from [Cu-I(tmpa)(CO)](+) in CH3CN (Delta H-dagger = 43.6 kJ mol(-1)), suggesting CO dissociation from copper regulates the binding of small molecules to the heme within [(L-6)Fe(II)center dot center dot Cu-I]+(3). Our observations are analagous to those observed for the heme(a3)/Cu-B active site of cytochrome c oxidase, where photodissociated CO from the heme(a3) site immediately (ps) transfers to CUB followed by millisecond transfer back to the heme.