Isoindolinone pigment

From the viewpoint of basic chromophore structures, organic pigments of commercial significance today may be classified into four major groups, namely 

in certain heterocyclic pigment molecules, the nature and spatial arrangement of the donor heteroatoms may be such as to make them ideally suitable as multidentate ligands, allowing the formation of very insoluble and heat 

High Performance Pigments. Edited by Edwin B. Faulkner and Russell J. Schwartz 

Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31405-8 

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A decisive step towards the development of isoindolinone pigments is credited to Geigy. Patents published in the late 1950s describe pigments with the basic structure 37, using tetrachlorophthalimide as starting material. 

The methine type comprises isoindoline derivatives which, like tetrachloro-isoindolinone pigments, have only recently been described. One or usually two equivalents of a compound containing an activated methylene moiety are attached to one equivalent of isoindoline. The list of compounds featuring activated methylene groups includes cyanacetamide or heterocycles such as barbituric acid or tetrahydroquinolinedione. 

P.Y.173, an isoindolinone pigment, affords somewhat dull, greenish yellow shades. It shows average fastness to organic solvents, especially to alcohols (ethanol), esters (ethyl acetate), and ketones (including methylethylketone and cyclohexanone). Its solvent resistance equals step 3 on the 5 step scale. P.Y.173 is almost completely to completely fast to mineral spirits and xylene. 

The recent isoindolinone pigment is already being withdrawn from the market. The commercially available grade had a coarse particle size and thus provided good hiding power. The pigment was recommended for use in various types of industrial paints, including automotive finishes. 

After Wodd War II the most important discovery was the family of red—violet quinacridone pigments, followed by the mosdy yellow-orange benzimidazolone and isoindolinone pigments, and the most recent development of the red diaryl pyrrolopyrroles. On a value basis, polycyclic pigments, excluding copper phthalocyanines, represent about 17% of the wodd oiganic pigment market (4). 

Babler, F. (1978). Stable gamma modification of an isoindolinone pigment—coloring PVC, lacquers, celluloseether(s) and ester(s) etc., in greenish-yellow shades. Ciba-Geigy AG Patent DE 2 804 062 GB 1 568 198. [26It]... 

Chem. Descrip. Isoindolinone pigment (Pigment yellow 139)... 

Isoindolinone pigments are high-performance pigments available in yellow, orange, and red. They can be used in most plastics. However, their high cost has limited them to specialty uses. 

All isoindolinone pigments are characterized by the presence of the isoindolinone ring structure 1. 

Even as late as the 1970s, Bitterli and Kehrer reported the preparation of yellow isoindolinone pigments starting with unsubstituted (R, = H) and dichloro (R, ... 

This represented a major breakthrough in the area of isoindolinone pigments, much of the work done on tetrachloroisoindolinones at Geigy being covered in an excellent comprehensive paper published by Pugin et al. l... 

Monomeric and polymeric phenylene-bridged azomethine-type isoindolinone pigments have been prepared, e.g., by the reaction of intermediates such as 21 and 22 with appropriate aromatic mono and diamines . ... 

In contrast, the exocyclic azomethine linkage (>C=N-) is remarkably stable in both alkaline and even acidic conditions. However, as soon as the isoindolinone pigments are dissolved in concentrated sulfuric acid under harsh conditions of temperature and solvent, they are hydrolytically cleaved into the corresponding diamine and phthalimide derivative. 

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