Synthesis and Characterization of Conjugated TPA-Based Azines Containing an Anthracene Moiety

Azines are a class of compounds with significant potential in materials science due to their good electronic and optical properties. In this study, a series of three novel compounds incorporating one, two, and three azine-type bonds was synthesized via an acetic acid-catalyzed condensation reaction between 9-anthraldehyde hydrazone (AN-2) and formylated derivatives of triphenylamine (TPA): 4-(diphenylamino) benzaldehyde (TPA-1), 4,4''-(phenylazinediyl) dibenzaldehyde (TPA-2), and 4,4',4''-nitrilotribenzaldehyde (TPA-3). The chemical structures of the resulting azines (AZ-1, AZ-2, and AZ-3) were confirmed by nuclear magnetic resonance (NMR), infrared (IR), and mass spectrometry (MS). Their thermal properties were further investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), while their electronic properties were examined via Ultraviolet‒visible (UV‒visible) spectroscopy. The results indicate that the three azines exhibit distinct thermal behaviors while demonstrating good thermal stability. Furthermore, the azine linkage between the TPA and anthracene moieties has minimal influence on the electronic properties of the compounds, suggesting a limited conjugation effect across the azine bridge. This finding provides valuable insights for the design of azine-based functional materials for future applications.