Dyes and pigments with high reflectance in the near-infrared (NIR) region can extensively control the heat buildup. Perylene-based pigments exhibit considerable reflectance in the NIR region. The reflectance of a material depends upon a number of factors, such as particle size, concentration of the reflective material, the distribution of particles within the material and the material's refractive index. The refractive index, in turn, depends on the electronic structure of the material. Therefore,differently substituted perylene compounds are expected to exhibit different reflectance in the NIR region. To elaborate this point, different perylene bisimide derivatives have been synthesized, and their ability to reflect in the NIR region has been determined and compared to the results for commercially available pigments. Significant variation in the relative reflectance is observed in the NIR region for differently substituted perylene bisimide compounds. The NIR reflectance of different perylene tetracarboxy diimide derivatives (PCIs) was also compared to the reflectance of 3,4:9,10-perylenetetracarboxylic dianhydride (PTCA), the precursor from which the PCIs are commonly synthesized. PICA exhibits significantly higher relative reflectance in the given region than any of the diimide derivatives synthesized from it in this study. (C) 2011 Elsevier Ltd. All rights reserved.
Selective interactions of perylene derivatives having different side chains with inter- and intramolecular G-quadruplex DNA structures. A correlation with telomerase inhibition
While the importance of the aromatic core in small organic molecules, studied as G-quadruplex mediated telomerase inhibitors, appears well studied by a number of researches, the role of side chains has been less well characterized. In this paper, we have studied the ability of six perylene derivatives with different side chains to induce both inter- and intramolecular G-quadruplex structures. The distance between the aromatic core and the positive charges in the side chains emerges as a significant molecular feature in G-quadruplex formation. Furthermore, the G-quadruplex formation appears also related to drugs 'self-association', influenced by the side chains basicity. The different efficiencies of the six perylene derivatives in interacting both with inter- and intramolecular G-quadruplex structures satisfactorily correlate with telomerase inhibition in cell-free systems. (C) 2004 Elsevier Ltd. All rights reserved.