The Solid-State Polymerization of 3,5-Dihalo-4-aminobenzoylchlorides: New Structural Perspectives

Heating 3,5-dihalo-4-aminobenzoylchlorides affords the analogous solid polybenzamides. X-Ray structure determinations of 3,5-dichloro-, 3,5-dibromo- and 3,5-diiodo-4-aminobenzoylchlorides reveal that all three structures contain infinite hydrogen-bonded chains of monomers in a head-to-tail arrangement (graph set notation C(8)), with amine-to-carbonyl carbon atom distances <4 Å. The proposal that the chain directions represent reaction pathways for the solid-state polymerization of the monomers is consistent with refractive index measurements made by Morgan over two decades ago.