Synthesis and characterization of 2-D and 3-D covalent networks derived from triazine central cores and bridging aromatic diamines

Nucleophilic substitutions of the reactive chlorine atoms in either cyanuric or phosphonitrilic chloride by the bridging 1,4-phenylenediamine and benzidine units lead to the formation of two-(2-D) or three-dimensional (3-D) covalent networks, according to the spatial arrangement of the chlorine atoms in each particular triazine core. The materials are electrochemically active and stable, and exhibit interesting optical properties. The UV-visible spectral absorptions are significantly red-shifted and can been altered upon chemical oxidation. Furthermore, a three-band absorption spectrum typical of polaronic nature is observed in the case of the layered benzidine/cyanuric chloride network. Either spherical (2-D) or cubic (3-D) morphologies were revealed by SEM analysis, while the XRD patterns indicated partial crystallinity. Due to the inherited ionexchange properties of the 2-D and 3-D ionic networks, the materials can be regarded as the organic analogues of conventional inorganic layered or zeolitic ion-exchangers. (c) 2008 Elsevier Ltd. All rights reserved.