Time dependency on the fabrication of H₄ TPPS₄^2--SnTPyP²⁺ porphyrin nanorods

Abstract

Meso-tetra(4-phenylsulfonic acid)porphyrin (H₄TPPS₄^2-) and tin(IV) meso-tetra(4-pyridyl)porphyrin dichloride (SnTPyP²⁺) porphyrin nanorods were prepared at room temperature by ionic self-assembly of these two oppositely charged porphyrins. The UV-VIS absorption spectra of the samples were measured hourly for the first six hours (after mixing the two porphyrin compounds) and then on a 24 hourly basis for 96 hour period. The spectra show a decrease in absorbance accompanied by a broadening of the absorption bands especially the J-aggregate bands with a red shift. This phenomenon was more pronounced after 24 hours, and no significant decrease in absorbance was observed after 72 hours. Transmission Electron Microscope (TEM) images of the product confirm the formation of the nanorods.

Keywords: Porphyrins, nanorods, J-aggregates, ionic self-assembly.