On the structure of erythritol and L-threitol in the solid state: An infrared spectroscopic study

FTIR spectra of crystalline erythritol and L-threitol were recorded between 4000 and 400 cm−1, at temperatures ranging from 298 K to 15 K. The most important bands were assigned by comparing the experimental and theoretical spectra. The latter were obtained from optimizations that started with the original crystal coordinates taken from the X-ray and neutron diffraction data, using the B3LYP/6-311++G(d, p) model chemistry. Spectra of the deuterated solids at 15 K were also used to help with the spectral assignments, particularly in the OH stretching region. The hydrogen bonding network of both isomers was the object of particular attention in the optimized conformations as well as in the crystalline solids. The possible existence of intramolecular hydrogen bonds in the optimized structures was checked by Atoms-In-Molecules (AIM) and Natural Bond Orbital (NBO) theories. A correlation between the spectroscopic results and the diffraction data was obtained.