Chain Packing in Two Aromatic Heterocylic Polymers, One of Which Has a Ladder Structure

摘要

A semiempirical method was used to calculate the interaction energies in the ladder polymer poly (3,6-dioxo-1H2,3,6,6a-tetrahydro-2,6a,11-tria zaindeno-1,2-pyrene-2,8,9-triy1-1-ylidene-1nitrilo) (BBL) and the single-strand polymer poly (5,8-dioxo-4b,5,8,8a-tetrahydro-4b,8a,13,16-tetraazadiindeno 1,2-A:1,2-I pyrene-3,10-diyl) (BBB), in order to elucidate their chain packing. The van der Waals contribution to the total intermolecular interaction energies was found to be more significant than the Coulombic one. The prediction of short-range interplanar spacings in the neighborhood of 3,3 A along the z axis (chains above one another) and 8,8 A along the y axis (chains alongside one another) is in good agreement with X-ray diffraction results. Keywords: Interaction energies, Aromatics, Heterocyclic polymers, Polymers, Packing arrangements, Molecular mechanics.