Synthesis and Characterization of [14]Thiatriphyrin(2.1.1) & Crystallization and Physical Properties of Thiatripyrrine Co-crystals

Abstract

In chapter 1 of the thesis, a thiophene containing triphyrin called [14] Thiatriphyrin(2.1.1) was synthesized by McMurry coupling of diformylthiatripyrrane followed by oxidation with p-chloranil. This was characterized by MALDI-TOF, HRMS, UV-Visible, 1H NMR, 1H-1H COSY and Single Crystal XRD spectroscopic techniques. These thiatriphyrins have a 14π-electron pathway and have non-planar structure probably due to the larger size of sulphur atom compared to inner nitrogen atoms and electronic repulsion between the lone pairs of nitrogen atoms. In chapter 2 of the thesis, the work focuses on the crystallization and physical properties of the thiatripyrrine co-crystals. Co-crystals of thiatripyrrine with dimethylformamide (DMF), acetonitrile and acetone have been examined. These co-crystals have been successfully prepared by dissolving thiatripyrrine in these molecules (used as solvent) and by passing the resulting solution through a syringe resulted in immediate nucleation. By varying the amount of thiatripyrrine and type of syringe, yield and productivity can be significantly increased. Single crystal X-ray diffraction was used to identify the 1:1 molar ratio of the parent compounds in the co-crystal. UV-Visible spectroscopy was used to check the reversibility of thiatripyrrine conformation in different solvents. The disintegration temperatures of co-crystals were determined by TGA and melting point. The formation of hydrogen bonds in thiatripyrrine co-crystals were investigated by FTIR. Computational studies were carried out to estimate the optimization energy of free thiatripyrrine conformation, the thiatripyrrine conformation in co-crystal and its other conformations along the dihedral angle.