INVESTIGATION ON THE STABLE AND STRONG LUMINESCENT MATERIALS CONTAINING PYRAZINE

本研究是由吡嗪衍生物在适当取代后显示出强发光的观察而开始的。在起始阶段，在吡嗪环的2-和5-位引入相同的芳基取代基。与对甲基苯基、苯基和对溴苯基衍生物相比，在吡嗪环的2-和5-位上带有两个给电子的对甲氧基苯基的化合物显示出更强的发光。萘基的引入比苯基的引入更能增强发光。在两个萘基中，2-萘基比1-萘基更有效，这表明共面共轭是重要的。带有两个苯并呋喃基的吡嗪具有较大的电子体系和给电子性质，具有最强的发光。为了了解取代基对吡嗪衍生物发光性能的影响。经过多次试验，我们确定了合成不对称取代吡嗪类化合物的方法。在12个化合物中，含5-甲基呋喃-2-基和2-萘基的吡嗪是本课题研究的最强发光材料，但其发光波长不太长，本课题的研究结果建立了吡嗪衍生物的合成方法，通过适当的取代基组合，可以得到发光强度较强的吡嗪衍生物。

This research was initiated by the observation that pyrazine derivatives showed strong luminescence if suitably substituted. In the initial stage, same aryl substituents were introduced at 2-and 5-position of pyrazine ring. Compared to p-methylpheny-, phenyl, and p-bromophenyl deribative, the compound bearing two electron-donating p-methoxyphenyl group at 2-and 5-position of pyrazine ring showed stronger luminescence. Introduction of naphthyl groups were effective than phenyl group in enhancing luminescence. Among two naphthyl group, 2-naphthyl group was more effective than 1-naphthyl group, which showed co-planer conjugation is important. The pyrazine, bearing of two benzofuran-2-yl group, which has large electron system and electron-donating character, showed strongest luminescence.Furthermore, we attempted to prepare, asymmetrically substituted pyrazines. In order to know the effect of the substituents on the luminescent properties of pyrazine derivatives. After several examination the method to synthesize asymmetrically substituted pyrazines could be developed. Among 12 compounds, the pyrazine having a 5-methylfuran-2-yl group and a 2-naphthyl group was the strongest luminescent material in our research, but the luminescence was observed at not so long wave length.By the results obtained in this project, the synthetic method for a variety of pyrazine derivatives was established and by suitable combination of the substituents strongly luminescent compound can be obtained.