Preparation and Optical Characterization of New Azo Merocyanine Dyes

Abstract

Merocyanine (MC) and azo dyes have many properties, e.g., high absorption and fluorescence. Also, they have photo-electrochemical properties. These dyes are highly sensitive to the changes in environmental factors; such as solvent polarity, temperature, light, and pH value. The difference of their properties increases their applications in many fields. They are used as photosensitizers for photodynamic therapy (PDT), due to their ability to treatment of cancer. In addition, they are used as spectral sensitizers for photography. They can be used as thin solid films for coating the different optical discs and optical recording media. The disadvantages of the azo MC dyes, prepared in the past, are the presence of contaminations and oxidation during the preparation. Also, their absorption bands are at short wavelengths. So, the publications concerning azo MC dyes and their applications are limited. The target of this study is the preparation of novel azo MC dyes with improved various properties by simple method and low cost to be used in many applications. Firstly, derivatives of novel azo MC dyes have been prepared. Then, their chemical characterization has been investigated by study the effect of solvents on these dyes. Their colors change with the change of solvent polarity. Their absorption spectra have shown three peaks of absorption bands in the range of wavelengths 333–360 nm, 400–519 nm and 630-760 nm in all solvents used.