A deuterium NMR and quantum chemical investigation of hydrogen bonding in organic solids

This thesis reports an investigation of hydrogen bonding in organic solids using solid-state 2H nuclear magnetic resonance and quantum chemical calculations. NMR measurements of deuterium chemical shifts (delta), nuclear quadrupolar coupling constants (chi) and asymmetry parameters (eta Q) have been performed on a variety of samples. For the first time, a C--H···O hydrogen bond has been investigated using solid state NMR spectroscopy. Existence of the C--H···O hydrogen bond has been demonstrated by comparing the values of delta, Deltadelta, chi, eta Q for the uncomplexed triphenylsilyl acetylene with the values for the triphenylsilyl acetylene-triphenylphosphine oxide. Samples containing two distinct hydrogen bonding situations have also been investigated; in most cases spectral resolution of the two separate spinning sideband manifolds has been achieved. Using the values of delta, chi and etaQ the relative strengths of the two hydrogen bonds have been inferred. Calculations have been performed and the values compare favourably with experimental results.