A two-dimensional dynamical parametrized model is derived to study the M-(H-2) interaction in transition-metal molecular hydrogen complexes. The parameters have been adjusted to reproduce the observed inelastic neutron scattering transitions through a least-squares fit procedure. The vibrational levels are obtained by solving the nuclear Schrodinger equation in a discrete variable representation. From this procedure, structural information such as the barrier to rotation of the Hz ligand and the H-H distance have been obtained. The accuracy of the model is tested on four systems with M-(H2) interactions of different nature. The resulting H-H bond distances are in very good agreement with neutron diffraction structures where available.