On The Origin Of Conformational Kinetic Isotope Effects

Document Type


Publication Date


Published In

Angewandte Chemie International Edition


Neatly dissected: The computed conformational kinetic isotope effects (KIEs) for biphenyls 1 and 2 (X=D or H) are in good agreement with experimental values and have been partitioned according to the Bigeleisen–Mayer and ΔH/ΔS approaches. In [D8]-1 the KIE is dominated by a normal entropic contribution which overshadows an enthalpic contribution determined by Hvib and not HZPE. The inverse isotope effect in [D6]-2 is governed by an enthalpic zero-point energy term (HZPE) working against a normal entropic contribution.