Synthesis and acidochromic, electrochromic properties of Schiff bases containing furan and triphenylamine units

• The SBs had excellent solubility in many common organic solvents.
• The SBs revealed good electrochromic and acidochromic characteristics.
• The SBs possessed good reversibility of color change.
• The SBs showed the good stability in potential step test.

A series of Schiff bases (SBs) were synthesized from 2-furancarboxaldehyde and different triphenylamine (TPA) derivatives to investigate the influence of substituted groups on the properties of SBs. The structures of SBs were characterized by means FTIR, NMR spectroscopy and elemental analysis (EA); the results showed an agreement with the proposed structure. The electrochemical, electrochromic and acidochromic properties of SBs were investigated by UV–vis spectroscopy and cyclic voltammetry (CV) techniques. The obtained SBs exhibited stable and reversible electrochromic properties. These anodic coloring films showed high coloration efficiency (CE). Furthermore, multiple reversible color states were also observed with the concentration changes of HCl vapor.

UV–vis absorption spectra of SB1 in the DMSO which protonated by HCl vapor in steps during the same time intervals. The concentration of pure SB1 was 0.04 mgL−1. Inset photographs indicated the color evolved in the process of doping HCl vapor.Figure optionsDownload as PowerPoint slide