Self-assembled centimetre-sized rods obtained in the oxidation of o-phenylenediamine and aniline

Morphologically well-defined rods of approximately 1 cm in length are effectively and economically obtained by mixing ortho-phenylenediamine (30 mmol L−1) with ammonium persulfate (12.5 mmol L−1) in an acidic solution (0.37 mol L−1 HCl) at room temperature with and without the presence of 50 mmol L−1 aniline. These self-assembled, morphologically uniform products can be potentially scaled up and used as morphological templates to fabricate well-defined structures of other materials such as conducting polymers. The products were characterized using Raman, UV-visible, high-resolution NMR (1H and 13C) and mass spectroscopies, X-ray diffraction, scanning electron microscopy and elemental analysis. Apart from certain differences in visual appearance and in X-ray diffractograms, other analytical data suggest that there are no structural changes upon addition of aniline into the reaction mixture. NMR and mass spectra imply that all syntheses carried out either with or without aniline result in a mixture of two products, attributed to 2,3-phenazinediamine and 3-aminophenazin-2-ol. A formation mechanism based on hydrogen bonding and π–π stacking has been proposed. © 2015 Society of Chemical Industry