W0255

X-Ray Diffraction, Neutron Scattering, DFT Calculations and the Study of Chemical Reactivity. Alberto Albinati, Univ. of Milan, Dept. of Structural Chemistry (DCSSI), Milan, Italy.

X-ray diffraction has always been of paramount importance in elucidating the solid state structures of co-ordination compounds and in improving our understanding of chemical reactivity, for example in showing how soluble chiral transition metal catalysts achieve asymmetric synthesis. When metal hydrides are involved, neutron diffraction is necessary to obtain the correct picture. The importance of transition metal hydrido-complexes (both classical and non-classical) in catalytic reactions, in particular hydrogenations, is well known and much work has been carried out in recent years to obtain a detailed understanding of the nature and reactivity of the M-H and M-H₂ moieties.

However, it is worth noting that a complete description of the reactivity in hydrido-compounds can only be achieved by combining the diffraction results with the knowledge of their dynamics that can be obtained from neutron incoherent inelastic scattering (INS) experiments.

I will discuss how neutron diffraction and INS data together with DFT calculations can provide a quantitative description of the rotational barrier and H₂/H exchange reaction in systems such as trans-(PⁱPr₃)₂IrXH₂(H₂) (X = Cl, Br, I) and (Tp^3,5-Me)RhH₂(H₂).