20 октября, 2015 
Pokraskin Dioxazine pigments are represented by the general structure 2:
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
The technically important pigments possess the substitution pattern displayed in the general structure. Typically, A represents an acetylamino or a benzoylamino group, B represents an ethoxy group and X is a chlorine atom or an HNCOCH3 moiety. Since production of Pigment Violet 34 and Pigment Violet 35 was discontinued several years ago there are currently only two dioxazine violets of commercial importance — Pigment Violet 23, which is used in considerable volume for miscellaneous applications including inks, plastics and coatings, and Pigment Violet 37, which is more of a specialty product and consequently used in somewhat lower volumes. Pigment Violet 37 corresponds to the general structure 2, where A and B represent a benzoylamino group and an ethoxy group respectively, E = H and X is an acetylamino group. The more commercially successful product, Pigment Violet 23 (also referred to as Carbazole Violet), is an exception to the general structural format since A and B or A and E are combined as part of a fused indole moiety formally resulting in the impressive polycyclocondensed structures, where Xj = X2 = Cl:
Traditionally, the product has been assumed to possess the linear molecular structure 4. However, comparison of the commercial product to one synthesized specifically to adopt the linear structure [3] exhibited differences between their respective visible spectra and other physical properties. Although speculative at that time, the data did imply the possibility that the actual molecular structure of Pigment Violet 23 was represented better by the “S” configuration resulting from angular ring fusion.
More recently [4], it has been demonstrated unequivocally, by single crystal X-ray diffraction analysis, that the molecular structure of Pigment Violet 23 does possess the angular configuration 3, the result of an A-E fusion. In conjunction with that same research it has been demonstrated also that the linear structure affords a blue shade product that apparently has no commercial importance as a pigment.
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