An unsymmetrical porphyrin and its metal complexes: synthesis, spectroscopy, thermal analysis and liquid crystal properties

• Main Authors: CHANGFU ZHUANG, XUEXIN TANG, DONG WANG, AIQING XIA, WENHUI LIAN, YUHUA SHI, TONGSHUN SHI
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2009-09-01
• Series: Journal of the Serbian Chemical Society
• Subjects: porphyrin; transition metal complex; fluorescence spectroscopy; liquid crystal
• Online Access: http://www.shd.org.rs/JSCS/Vol74/No10/08_4354_3903.pdf

The synthesis and characterization of a new unsymmetrical porphyrin liquid crystal, 5-(4-stearoyloxyphenyl)phenyl-10,15,20-triphenylporphyrin (SPTPPH2) and its transition metal complexes (SPTPPM, M(II) = Zn, Fe, Co, Ni, Cu or Mn) are reported. Their structure and properties were studied by elemental analysis, and UV–Vis, IR, mass and 1H-HMR spectroscopy. Their luminescent properties were studied by excitation and emission spectroscopy. The quantum yields of the S1 ® S0 fluorescence were measured at room temperature. According to thermal studies, the complexes have a higher thermal stability (no decomposition until 200 °C). Differential scanning calorimetry (DSC) data and an optical textural photograph, obtained using a polarizing microscope (POM), indicate that the porphyrin ligand had liquid crystalline character and that it exhibited more than one mesophase and a low-lying phase transition temperature, with transition temperatures of 19.3 and 79.4 °C; the temperature range of the liquid crystal (LC) phase of the ligand was 70.1 °C.