A series of Group 7 organometallic noble gas complexes, (eta(5)-C5R5)M(CO)(2)L(M = Mn and Re; R = H, Me. and Et (Mn only); L = Kr and Xe) have been characterized in supercritical noble gas solution at room temperature using fast time-resolved infrared spectroscopy. The kinetics and activation parameters for the reaction of these complexes with CO were measured and compared to the analogous alkane complexes, (eta(5)-C5H5)M(CO)(2)(n-heptane) (M = Mn and Re). Evidence obtained from values of the activation enthalpies and experiments, in which the lifetimes of (eta(5)-C5R5)Mn(CO)(2)Xe (R = H, Me, and Et) were measured as a function of [CO] at a constant [CO]/[Xe] ratio, suggests that the reaction of the noble gas complexes with CO occurs mainly via a dissociative or dissociative interchange mechanism.