TY - JOUR AU - Parrott, Edward P. J. AU - Zeitler, J. Axel AU - Fris<152>c<152>ic<81>, Tomislav AU - Pepper, Michael AU - Jones, William AU - Day, Graeme M. AU - Gladden, Lynn F. PY - 2009 DA - 2009// TI - Testing the sensitivity of terahertz spectroscopy to changes in molecular and supramolecular structure: a study of structurally similar cocrystals T2 - Crystal Growth & Design JO - Crystal Growth & Design SP - 1452 EP - 1460 VL - 9 IS - 3 KW - supramolecular recognition KW - infrared KW - terahertz KW - IR KW - THz KW - TDS AB - Terahertz time-domain-spectroscopy (THz-TDS) has emerged as a versatile spectroscopic technique, and an alternative to powder X-ray diffraction in the characterization of molecular crystals. We tested the ability of terahertz spectroscopy to distinguish between chiral and racemic hydrogen-bonded cocrystals that are similar in molecular and supramolecular structure. Terahertz spectroscopy readily distinguished between the isostructural cocrystals of theophylline with chiral and racemic forms of malic acid which are almost identical in molecular structure and supramolecular architecture. Similarly, the cocrystals of theophylline with chiral and racemic forms of tartaric acid, which are similar at the molecular level but dissimilar in crystal packing, were distinguished unequivocally. The investigation of the same cocrystals using X-ray powder diffraction and Raman spectroscopy suggested that THz-TDS is comparable in sensitivity to diffraction methods and more sensitive than Raman spectroscopy to changes in cocrystal architecture. The differences in spectra acquired by THz-TDS could be further enhanced by cooling the samples to 109 K. SN - 1528-7483 UR - http://pubs.acs.org/doi/abs/10.1021/cg8008893 UR - https://doi.org/10.1021/cg8008893 DO - 10.1021/cg8008893 N1 - exported from refbase (https://db.rplab.ru/refbase/show.php?record=567), last updated on Thu, 19 Mar 2009 17:52:40 -0500 ID - Parrott_etal2009 ER -