SYNTHESES AND PHOTO-FUNCTIONALITY DESIGN OF UNSYMMETRICALLY SUBSTITUTED BIPYRIDINES

有机荧光颜料因其在各种领域的潜在应用而引起了人们的极大兴趣。在本项目中，我们致力于开发具有不对称取代基的2，2‘-联吡啶结构的新型有机荧光颜料(S)。初步结果表明，6，6‘-二氨基-2，2’-联吡啶(DABP)具有很强的荧光。合成了一系列氨基和氯取代的联吡啶类化合物，发现6-氨基取代基是在溶液和固体中产生强蓝色荧光所必需的。其中，不对称取代的6-氨基-6‘-氯-2，2’-联吡啶(AcBP)的发光强度最强(Phi=0.8)，具有较大的Stokes位移(约90 nm)，当在三层EL器件中制备DABP和AcBP时，观察到较弱的电致发光。由于每个吡啶单元上具有供电子和吸电子取代基的AcBP具有最强的荧光强度和较大的Stokes位移，推测了激发态两个吡啶单元之间的分子内电荷转移可能起到了作用。在这些结果的基础上，合成了具有较大斯托克斯位移的扭曲分子内电荷转移(TICT)发射的新的芳酰胺类主体分子，结果表明具有三个氢键的尿嘧啶衍生物的分子识别直接受到TICT发射的调制，在较长波长一侧的质子溶剂中观察到的DABP的弱发射归因于酰亚胺互变异构体。在此基础上，合成了DABP的烷基衍生物，该衍生物能够通过多个氢键相互作用识别脂肪酸，并通过改变酰胺-酰亚胺互变异构化的发射来监测这种相互作用。

Organic fluorescent pigment has been attracting considerable interest because of its potential application in variety of fields. In this project, we focused on developing new organic fluorescent pigment that has the 2,2'-bipyridine structure with unsymmetrical substituent(s). Preliminary results revealed that 6,6'-diamino-2,2'-bipyridine(dabp) showed strong fluorescence. A series of amino and chloro substituted bipyridines was synthesized, and it was found that 6-amino substituent was essential for strong blue fluorescence in solution and in solid. Among them, unsymmetrically substituted 6-amino-6'-chloro-2,2'-bipyridine(acbp) showed strongest emission (phi=0.8) with large Stokes shift(ca 90 nm), and weak electroluminescence was observed when dabp and acbp were fabricated in three layr-type EL device.As acbp that has electron-donating and electron-withdrawing substituents on each pyridine unit showed strongest fluorescence with a large Stokes shift, possible role of intramolecular charge transfer between the two pyridine units at excited state was suggested. On the basis of these results, new aromatic amide-type host molecule that showed a twisted intramolecular charge transfer(TICT) emission with a large Stokes shift was synthesized, and it was shown that molecular recognition of the uracil derivatives with triple hydrogen bonding was directly monitored by modulation of the TICT emission.Weak emission of dabp observed in protonic solvent at longer wavelength side was ascribed to the imide tautomer. Based on this observation, alkyl derivatives of dabp were synthesized, and the derivative demonstrated the ability to recognize fatty acids by multiple hydrogen bonding interaction and to monitor the interaction by alteration of its emission due to the amide-imide tautomerization.