Composites of Perylene Chromophores and Layered Double Hydroxides: Direct Synthesis, Characterization, and Photo- and Chemical Stability

摘要

Composites of the tetra-anion of the perylene dye N,N'-di(phenyl-3,5-disulfonic acid)perylene-3,4:9,10-tetracarboxydiimide (PBITS) with layered double hydroxides (LDHs) were formed by direct synthesis (co-precipitation at constant pH). The LDHs were of the hydrotalcite (Mg-Al-OH and Zn-Al-OH compositions). During synthesis of the hydrocalumite type (Ca-Al-OH), partial destruction of the dye occurs, being more pronounced at higher pH values. The composites were characterized with regard to their composition by elemental and thermal analysis. From UV-vis spectroscopic data and powder X-ray diffraction, a structural model is developed for the composites. In the galleries between the hydroxide layers, the chromophore molecules are stacked in an J-type arrangement. The compounds have brilliant colors and are insoluble in common solvents. With regard to a possible application as pigments, their photostability and their chemical resistance against a typical application environment was tested. The photostability of the dye molecules and their chemical resistance against setting cement are slightly raised by the occlusion within the LDH structure; however, the photostability of the LDH-cement is lower than that of cement colored with the pure perylene dye.