Synthesis and Photoluminescent Properties of Violet Emitting 5,6-Diphenylfuro[2,3-d]pyrimidine Derivatives

Abstract

Furopyrimidines have known to possess antitumor, analgesic, antihypertensive, anti-inflammatory activity, and to inhibit adenosine kinase in very low concentration. Recently, we found that various furopyrimidine derivatives had optical properties to apply for organic light-emitting diodes (OLED) or fluorescent dye. Organic electroluminescent diode has undergone dramatic improvement since pioneering work of Tang and VanSlyke. Much progress has made especially in recent year, including the development of device fabrication, good material, and construction of manufacture infrastructure. It is necessary to have a set of red, green, and blue emitting materials with excellent luminous efficiency, proper chromaticity and the photochemical stability of emitters for an emitting layer for OLED. Though many organic, polymeric and inorganic emitting materials have been reported, many breakthroughs have to be achieved on the field of materials for excellent efficiency of OLEDs. Therefore, we report the synthesis of furopyrimidine derivatives and their photoluminescent properties. Furopyrimidines (1-9) were obtained in high yield in five steps, starting from the reaction of furoin with malonitrile in the presence of diethyl amine, as shown in Scheme 1. The absorption spectra and photoluminescent spectra of the compounds (1-9) were monitered using dichloromethane on the concentration of 50 μM by UV/Vis spectroscopy and luminescent spectroscopy, and their results were showed in Table 1 and typical example of spectrum was shown in Figure 1 for 1, 5 and 7. The full widths at half maximum value of all compounds were between 59 and 91 nm, showing generally good color purity. Thermogravimetric analysis (TGA, 50-500 C, 20 C/min, N2) of 5 showed an onset of weight loss at 243 C, 10% weight loss at 270 C, and over 90% weight loss 382 C. The onset temperature of weight loss of compounds 1-4 and 6-9 were between 210 and 250 C. All furopyrimidine derivatives (1-9) displayed intenser photoluminescence (PL) in concentration of 50 μM CH2Cl2