Synthesis And Characterization Of Pyrazoline Fluorescent Compounds Containing Pyrimidyl

Light-emitting materials have been through the long history in human civilization. Organic fluorescent compounds hold a great proportion in existent several fluorescent compounds. They are mostly applied to the plastics, organic fluorescent pigments, fluorescent origin, coatings, optical whitening agent, dyes and other fields. With development and updating of synthesis and packaging technology, organic luminescent materials are interruptedly used in the field of electroluminescence. Moreover, entered the information age, to satisfy the required of all kinds of information show, luminescent materials have been developed quickly. Organic luminescent material has a higher luminous efficiency, as well as a wider scope of color choices and has the benefits of easy great-scale film.In the paper, according to Schellhammer inference of the relation between chemical structure and fluorescent feature, new fluorescent compounds had been designed and synthesized, which comprised the benzothiazolyl in the 1-pyrazoline, the pyrimidyl in the 3-pyrazoline. Synthetic technology of the compound was researched in detail. And the reaction conditions of every reaction were debated, and the optimum synthetic conditions of each step were decided. The structure of compounds was proved by means of IR spectrum, MS, element analysis and 1H NMR. Urea, acetylacetone, aniline, and mellowness were used as material to synthesis the pyrazoline compounds, by a,β-unsaturated ketone and hydrazine under a condition of alkalescency environment with the cyclization. Analyzed and researched their fluorescence capability. It was shown from the tests of fluorescent compounds that the maximal absorb wavelength were about 350nm, the fluorescence emanation wavelengths were about 450nm, these compounds had excellent fluorescence with blue light. The influence of the structure of the compound on fluorescent performance is discussed. The fluorescent properties could be influenced by solvent polarity and as the polarity of solvent increasing, the fluorescent strength of substances enhanced, the largest emanation wavelength red shift happened, the largest fluorescence excitation wavelength blue shift occurred, but fluorescence quantum turnout had little change. Moreover, it was displayed that the fluorescence quantum yield of the fluorescence compounds was little influenced by the replaced group and polarity of the solution. There was not directly related between the fluorescence quantum yield and fluorescence intensity of compounds.