Carbonyl pigments: Miscellaneous types

Carbonyl pigments are characterized by the presence of one or more carbonyl (C = O) groups in their structures, generally as a component of the chromophoric grouping and as part of an extended conjugated π-electron system. Structurally, they constitute a diverse group of pigments that offer a wide range of colors throughout the spectrum, and most of them provide high levels of technical performance. This paper provides a description of the historical development of thioindigoid, isoindoline, isoindolinone, and quinophthalone pigment types, and discusses their molecular and crystal structures in relation to their properties, the synthetic procedures used in their manufacture and their principal applications. They provide some of the most important high-performance yellow organic pigments for demanding applications in paints, inks, and plastics. Separate individual chapters in this series are devoted the anthraquinonoid, quinacridone, diketopyrrolopyrrole, perylene, and perinone carbonyl pigment subclasses.