Non-conjugated polyamines with near-infrared electrochromic and photoelectric response prepared via reducing PolySchiff bases by NaBH4

A simple approach to obtain a series of polyamines (RPSBs) based on N,N′-bis(4-aminophenyl)-N,N′-bis(α-naphthyl)-bisphenylenediamine via reducing conjugated PolySchiff bases (PSBs) by NaBH4 is presented in this article. The structures and molecular weights of RPSB were characterized by means of FTIR, 1H NMR, and GPC which showed an agreement with the proposed ones. The RPSBs exhibited excellent solubility in many polar organic solvents, with inheriting good electrochromic characteristics. They displayed obvious absorption and fluorescence responses upon the addition of trifluoroacetic acid or HCl, with high sensitivity and specificity. The results of TGA and DSC show that the RPSBs are heat resistant and amorphous. The energy bands were calculated to be in the range of 2.09–2.55 eV by using the cyclic voltammetry combined with the UV–vis spectra. The hybrid density functional theory (DFT) method was used to calculate the optimized geometry and electronic structure of RPSBs. SEM images show that the RPSBs were facile to self assemble into spherelike particles.