Factors Governing the 3-Dimensional Hydrogen-Bond Network Structure of Poly(m-phenylene isophthalamide) and a Series of Its Model Compounds (2) Computer Simulation of Crystal Structures of Aromatic Amide Compounds and Comparison with X-ray Analyzed Structures

Crystal structures have been predicted by using a software Polymorph Predictor and compared with those analyzed by X-ray method for a series of low-molecular-weight aromatic amide compounds as models of poly(m-phenylene isophthalamide) and poly(p-phenylene terephthalamide). For most of the compounds investigated here, the predicted crystal structure of the lowest or the next lowest packing energy has been found to be in good agreement with the X-ray analyzed structure. However, the energy difference was not very large between these energetically most plausible structures and the other less stable candidates, indicating a difficulty of unique prediction of 3D molecular packing structure and a possibility of existence of various types of crystal modification.