X-Ray crystallographic studies of three substituted indium(iii) phthalocyanines: effect of ring substitution and the axial ligand on molecular geometry and packing

Abstract

Crystal structure analyses of a series of three substituted indium phthalocyanines, viz., chloro[1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyaninato]indium(III), 1, 4-fluorophenyl[1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyaninato]indium(III), 2, and racemic chloro[2-bromo-1,4-dibutoxy-8,11,15,18,22,25-hexakis(hexyl)phthalocyaninato]indium(III), 3, are reported. Despite varying the axial ligand from a chloro group to the more space demanding 4-fluorophenyl group, and introducing somewhat different substituents onto one of the benzenoid rings of one of the derivatives, the three compounds form similar types of columnar stacks. Key components of the stack structure are concave–concave pairs of molecules. The molecules are offset but allow for a significant degree of overlap. Components of these pairs then participate in a lower area convex–convex overlap with adjacent pairs to form an offset column of pairs. However, one of the compounds, 1, shows a different type of global packing to the other two. For this compound, the molecules of one column are tilted with respect to those in an adjacent column and thus exhibit a type of herring bone arrangement; the molecules of the other two compounds pack with their central planes parallel. All three compounds form apparently even and transparent films by the spin coating method. UV-vis spectroscopy shows that the visible region absorption band is shifted to the red relative to the solution phase spectra.