Ab initio accelerated molecular dynamics study of the hydride ligands in the ruthenium complex: Ru(H 2 ) 2 H 2 (P(C 5 H 9 ) 3 ) 2 .

The dihydrogen complex Ru(H-2)(2)H-2(P(C5H9)(3))(2) has been investigated, via ab initio accelerated molecular dynamics, to elucidate the H ligands dynamics and possible reaction paths for H-2/H exchange. We have characterized the free energy landscape associated with the H atoms positional exchange around the Ru centre. From the free energy landscape, we have been able to estimate a barrier of 6 kcal mol(-1) for the H-2/H exchange process. We have also observed a trihydrogen intermediate as a passing state along some of the possible reaction pathways.