The picosecond time-resolved infrared spectra of (CN)(5)FeCNRu(NH3)(5)(-) were collected following optical excitation and reverse electron transfer. The measured reverse electron transfer rates are greater than 3 x 10(12) s(-1). In both formamide and deuterated water solutions, vibrational excitation in CN stretch modes is found after reverse electron transfer, The transient spectra at both earlier (1-35 ps) and later (10 ns) times give evidence of environment-solute coupling that can be accounted for by solvent heating and ion pair dynamics. A simulation of the spectral dynamics in formamide solution is presented using a kinetic model for vibrational excitation and relaxation. The simulation includes minor excitation in vibrational modes consistent with resonance Raman derived Franck-Condon factors, but it is also found that a nontotally symmetric mode is equally important as an acceptor.