X-Form metal-free phthalocyanine: crystal structure determination using a combination of high-resolution X-ray powder diffraction and molecular modelling techniques

Abstract

A combination of high resolution X-ray diffraction and molecular modelling techniques have been used to determine (R_wp= 12.51%) the crystal structure of the X-form of metal-free phthalocyanine. It was found to crystallise in a bimolecular monoclinic unit cell (space group P2₁/a) with lattice parameters a= 10.63, b= 23.15, c= 4.89 Å, β= 95.98° in a ‘herring-bone’ molecular packing motif with a smaller angle (50°) than is found in the more stable β-polymorph (89°).