In this work, we investigate the intramolecular vibrational energy redistribution associated with the hydrogen transfer in a derivative of tropolone, namely 3,7-dichlorotropolone. Our quantum simulation is based on the Cartesian reaction surface Hamiltonian together with the multi-configurational time-dependent Hartree approach for the wave-packet propagation. We compare results for two model systems with 6 and 14 dimensions, respectively. The 6D model accounts for the most strongly coupled modes, whereas the 14D model includes further modes with significantly weaker couplings. The linear absorption spectrum of both models shows the development of an OH-stretching band. Furthermore the results show that despite the fact, that the additional modes in the 14D system couple significantly weaker, there are qualitative differences in the decay behavior of an OH-stretching excitation. Limitations of the present reaction surface approach are also discussed.