New Quinacridone Pigments

Crystal structure prediction of organic pigments: quinacridone as an example

The structures of the alpha, beta and gamma polymorphs of quinacridone (Pigment Violet 19) were predicted using Polymorph Predictor software in combination with X-ray powder diffraction patterns of limited quality. After generation and energy minimization of the possible structures, their powder patterns were compared with the experimental ones. On this basis, candidate structures for the polym...

Quinacridone-Diketopyrrolopyrrole-Based Polymers for Organic Field-Effect Transistors

Incorporation of pigment or dye molecules as building units is of great interest in the development of semiconducting polymers, due to their strong intermolecular interactions arising from the strong local dipoles in the unit structure, which would facilitate the charge transport property. In this paper, semiconducting polymers based on well-known pigments, namely, quinacridone and diketopyrrol...

Tracking Mammals with Fluorescent Pigments: a New Technique

The genetics of New World monkey visual pigments

To have color vision, having at least two cone photopigment types with different spectral sensitivities present in distinct photoreceptors is necessary together with the neural circuitry necessary to extract color information. Visual pigments are highly conserved molecules, but differences can be found among vertebrate groups. Primates have a variety of cone photopigments (i.e., opsins) that ar...

A New Class of Flavone Pigments in the Palmae

In the course of a chemotaxonomic flavonoid survey of monocotyledonous families related to the grasses attention was turned to flavonoids in leaves of the Palmae. Many of the flavonoids present were readily identified as known pigments2. Thus, the flavonols, kaempferol and quercetin, and the flavones, apigenin and luteolin, were variously detected in glycosidic combination. Glycosylflavones bas...