Spectroscopic properties and cyclic voltammetry on a series of meso-tetra(p-alkylamidophenyl)porphyrin liquid crystals and their Mn complexes

A series of meso-tetra(p-alkylamidophenyl)porphyrin ligands and their manganese(III) complexes are reported in this paper. The mesomorphism was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) and the results show that only the porphyrin ligands with long side chains show liquid crystalline behavior, and they exhibit a high phase transition temperature and a broad mesophase temperature span. Furthermore, we investigated the properties of the compounds by means of UV−vis spectra, infrared spectra, Resonance Raman spectra, fluorescence spectra, thermal analysis and cyclic voltammetry. These studies indicate that the length of side chains has little effect on the properties of porphyrin compounds. According to thermal studies, the decomposition of porphyrin ligand and Mn complex is a continuous process.