Model Compound Studies of Rigid Rod Aromatic Heterocyclic Polymer Systems. Part I. The Crystal and Molecular Structures of 2,6-Diphenylbenzo (1,2-d:4,5-d') Bisthiazole & 2,6-Diphenylbenzo (1,2-d:5,4-d') Bisoxazole

摘要

The x-ray crystal structures of two monomeric model compounds for polybisbenzoxazole (PBO) and polybisbenzthiazole (PBT) are presented. The PBO model compound molecules stack along the b crystallographic axis in two vertical columns of differing orientation and are inclined to b by an angle of 36 deg. The repeat distance along b is 5.94A and the perpendicular distance between adjacent molecules in a particular stack is 3.4A. The PBT model compound molecules stack most efficiently along its b crystallographic axis with an inclination angle of 36.8 deg. Adjacent molecules along c exhibit a crossing pattern with a dihedral angle of 73.6 deg. The relationship between the model compound structures and the gross packing features of polymer chains in PBO and PBT are discussed. (Author)