Diketopyrrolo-Pyrrole DPP Pigments

The basic skeleton of this newly developed group of pigments consists of two anel-lated five-membered rings each of which contains a carbonamide moiety in the ring. 

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All polycyclic pigments, with the exception of triphenylmethyl derivatives, comprise anellated aromatic and/or heteroaromatic moieties. In commercial pigments, these may range from systems such as diketopyrrolo-pyrrol derivatives, which feature two five-membered heteroaromatic fused rings (DPP pigments) to such eight-membered ring systems as flavanthrone or pyranthrone. The phthalo-cyanine skeleton with its polycylic metal complex is somewhat unique in this respect. 

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