Uses
Smart materials with tunable multiple-color emissions have been widely investigated in the fields of bioimaging, display, and information encryption. Multicolor emissive molecules with hydrazone bridged triphenylamines and pyridinium groups can be produced from 4-Di-p-tolylamino-benzaldehyde.
4-Di-p-tolylamino-benzaldehyde (0.603 g, 2 mmol) and 2-Hydrazinopyridine (0.442 g, 4 mmol) were stirred in 15 mL methanol at 90 °C for 24 h. After cooling to room temperature, the yellow crude product is extracted and filtered directly. Then yellow rod-like crystals were obtained by recrystallization in ethanol
[1].
Synthesis
N,N-dimethylformamide (2.74 g, 37.5 mmol) was slowly added dropwise to a mixed system of 4,4'-dimethyltriphenylamine (2.27 g, 18.8 mmol) and phosphorus trichloride (5.65 g, 22.5 mmol) at 25 °C. The reaction mixture was continuously stirred and heated at 130 °C for 6 hours. Upon completion of the reaction, the system was cooled to room temperature and subsequently poured into 50 mL of cold water and extracted with chloroform (3 x 15 mL). The organic phases were combined, dried with anhydrous magnesium sulfate and filtered. Purification by recrystallization from dilute ethanol afforded the target product 4-di-p-tolylaminobenzaldehyde (R2-CHO). Yield: 1.75 g (31.5% yield). The melting point of the product was 96.3-97.5 °C. Electrospray ionization mass spectrometry (ESI-MS) showed the molecular ion peak ([M + H]+) m/z was 302.4.
References
[1] Chemical Communications, 2014, vol. 50, # 52, p. 6869 - 6871
[2] Dyes and Pigments, 2011, vol. 88, # 3, p. 333 - 343
[3] Tetrahedron, 2003, vol. 59, # 25, p. 4673 - 4685
[4] Dyes and Pigments, 2014, vol. 108, p. 32 - 40
[5] Journal of Chemical Crystallography, 2000, vol. 30, # 11, p. 749 - 753
