Isotopic perturbation method temperature dependence

The isotopic perturbation of resonance (IPR) method for ti -H2 characterization depends on the observation of differing chemical shifts and temperature-dependent isotope fractionation in partially deuterated polyhydrides. IPR has been shown to correctly indicate classical configurations, despite low Ti values, for many rhenium polyhydrides.However, IPR sometimes proves useless due to insignificantly small chemical shifts and broad signals. Alternatively, deuteration may exert an influence on equilibria, such as that shown in Eq. (1). Deuteration increases the abundance of (2). However, this effect is offset by greater intramolecular fractionation of deuterium into the ri site of (2) resulting in little IPR shift. 

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