Molecular stacks as a common characteristic in the crystal lattice of organic pigment dyes - A contribution to the "soluble-insoluble" dichotomy of dyes and pigments from the technological point of view

This is the first attempt at trying to arrange industrial organic pigments into an order from the viewpoint of the formation of molecular stacks as the common characteristic of all their crystals. Some pigments additionally form networks of leaf-like structures, and others assemble themselves to construct a three-dimensional lattice. This approach is new in the field of pigments, but it permits differences in solubility behavior to be readily explained in a qualitative manner. Crystal engineering is undoubtedly the scientific basis for organic solids and may be vividly described as providing the building blocks, cement and brickwork for pigment dyes (heterocycles). Significant developments in organic pigments were admittedly, however-following the demands of both technology and market forces-made long before the new discipline of crystal engineering was called into being. The pigment dyes are thus an intimate point of contact between science and technology. (C) 2003 Elsevier Ltd. All rights reserved.