Acta Scientiarum Naturalium Universitatis Pekinensis

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Thermal Behaviors and Crystal Structure of Hemicyanines

WANG Kezhi1, HUANG Chunhui1, ZHOU Yongfen1, XU Guangxian1, ZHOU Qifeng2, LIN Xiuyun3   

  1. 1State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871; 2College of Chemistry and Molecular Engineering, Peking University, Beijing,100871; 3Institute of Biophysics, Academia Sinica, Beijing, 100101
  • Received:1994-04-20 Online:1996-03-20 Published:1996-03-20

半菁化合物热行为和晶体结构的研究

王科志1, 黄春辉1, 周永芬1, 徐光宪1, 周其凤2, 林秀云3   

  1. 1北京大学稀土材料化学与应用国家重点实验室,北京,100871; 2北京大学化学与分子工程学院,北京,100871; 3中国科学院生物物理研究所,北京,100101

Abstract: 5 hemicyanines with the compositions of Me2NC64CH=CHC54NCnH2n+1Br (n=16, 12, 4, 2 and 1) have been synthesized and characterized by elemental analysis, thermalgravimetric, differential thermal analysis (TG-DTA), differential scan calorimetry (DSC), ultraviolet and infrared spectroscopy. For the first time, a hemicyanine Me2NC64CH=CHC54NC1633Br has been characterized to be of a mesogenic behavior with typical focal conical texture. The structure of Me2NC64CH=CHC54NC25Br.nH2O has been determined by singal crystal X-ray diffraction. The crystal belong to monoclinic, P21/C space group. The crystal parameters are as follows: a=1.6125(8), b=1.7391(12), c=1.8784(8) nm, β=99.794(8)°, V=5.220(5) nm, Z=12.

Key words: hemicyanine, liquid crystal, crystal structure

摘要: 合成了5个不同烷基链长的半菁化合物:Me2NC64CH=CHC54 NCnH2n+1Br(n=16, 12, 4, 2和1)。由可见光谱、红外光谱、差热(DTA)、热重(TG)谱、微分扫描量热分析和偏光显微镜研究结果,讨论了烷基链长的变化对半菁化合物有关性质的影响。首次发现n=16时半菁化合物为近晶型双变性液晶,90°偏光显微镜下,呈典型的焦锥织态结构。测定了化合物Me2NC64CH=CHC54NC25Br·nH2O的晶体结构。晶体属单斜晶系,空间群P21/C,晶胞参数:a=1.6125(9), b=1.739 1(12), c=1.878 4(8) nm, β=99.794(8)°, V=5.220(5) nm3, Z=12。

关键词: 半菁, 液晶, 晶体结构

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