Synthesis and investigation on optoelectronic properties of mesogenic triphenylene–perylene dyads linked by ethynylphenyl bridges
作者:Xiangfei Kong、Hongkang Gong、Peng Liu、Wei Yao、Zheng Liu、Guixia Wang、Shufen Zhang、Zhiqun He
DOI:10.1039/c7nj04328g
日期:——
of light absorption of the perylene units was independent of the bridge lengths, while that of the triphenylene units was red-shifted with the increase of the bridge lengths. 2D and 3D photoluminescence emission showed that the fluorescence quenching degree of perylene units increased as the rigid bridges became shorter. According to the energylevel structures of the dyads, fluorescence quenching was
制备具有乙炔基苯基桥连接到a单酰亚胺二己基酯受体的酰亚胺氮原子上的五(己氧基)三亚苯基供体的光化学电子给体-受体二元体,得到TP- n -PIE(n = 1、2和3)。其分子结构的特征是13 C和1H核磁共振(NMR)光谱,红外光谱(IR),质谱(MS)和元素分析(EA)。差示扫描量热法(DSC)迹线,偏振光学显微镜(POM)纹理和X射线衍射图证实较短的乙炔基苯基桥促进了柱状六角形液晶相的形成。ylene单元的光吸收强度与桥长度无关,而三亚苯基单元的光吸收强度随桥长度的增加而红移。2D和3D光致发光显示,随着刚性桥的变短,per单元的荧光猝灭程度增加。根据二联体的能级结构,荧光猝灭归因于分子内光诱导的电子转移过程。TP + ˙-1- PIE - ˙,进一步通过光电流响应曲线可以证实,获得。循环伏安法表明,尽管乙炔基桥与三亚苯基单元共轭连接,但当桥占据时,最高占据分子轨道(HOMO)能级,最
π-Conjugated Triphenylene Twins Exhibiting Polymesomorphism Including the Nematic Phase
作者:Sanjay Kumar Varshney、Hideo Takezoe、Veena Prasad、D. S. Shankar Rao
DOI:10.1080/15421400902987677
日期:2009.12.7
Novel discotic liquid crystals possessing two triphenylene (TP) mesogenic cores covalently connected via a rigid spacer, i.e., -conjugated ethynyl- or butadiynyl-bridge, (TP twins) are reported. The TP twins are categorized by the lengths of -substituted chains (R2 and R3) and peripheral alkoxy or branched aliphatic chains (R1 and R4). Three varieties of TP twins are prepared: A) TP twins having identical -substituted and peripheral chains (R1=R2=R3=R4), B) equivalent TP entities having a -substituted chain (R2=R3) and peripheral chains (R1=R4) of different length from the substitution, and C) TP twins with different TP entities having the same -substituted and peripheral alkoxy chains (R1=R2, R3=R4). The phase behavior is characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) studies. These TP twins exhibit a discotic nematic (N) and/or columnar rectangular (Colr) mesophases over a wide temperature range. We found that the relative length of rigid spacer and -substituted alkoxy chains play an important role in the creation of the molecular self-assembly and formation of the mesophases. To the best of our knowledge, this is the first report of TP twins exhibiting polymesomorphism.