Green synthesis of aryl‐(4‐oxo‐1,2‐dihydroquinazolin‐4‐yl‐methylene) pyrazole‐TiO₂ nanoparticles as dyes removable for waste water treatment

Abstract

Facile synthesis for true intermediate (E)‐ and Z‐2‐(((5‐bromo‐1‐(3‐chloropyridin‐2‐yl)‐1H‐pyrazol‐3‐yl)methylene)amino)‐5‐chloro‐3‐methylbenzoic acid precursors and 2‐(5‐bromo‐1‐(3‐chloropyridin‐2‐yl)‐1H‐pyrazol‐3‐yl)‐6‐chloro‐3,8‐dimethylquinazolin‐4(3H)‐one (QPP) as electron donor/electron acceptor to be working as efficient dye sensitizers. These new derivatives have a wide‐band gap photo‐catalysts semiconductor and are performing to spread to the visible‐light region to give more stability and efficiency towards biomedicine for different diseases. In the present work, the authors are suggesting the design and synthesis of new structures of QPP molecule with extended visible light absorptivity due to the extended π‐π/n‐π conjugations, to stimulate TiO2 nanoparticles in visible‐light region. The physicochemical characterizations confirmed the successful synthesis of QPP, TiO2, and QPP II/TiO2 samples with the proposed structures. Fixing of QPP on the TiO2 surface is refining the optical properties of TiO2 with enhancing the charge separation and generating the efficient antenna in the visible region. Furthermore, the QPP II/TiO2 sample achieved a threefold enhancement in the observed rate constant of the photo‐degradation of rhodamine B dye when compared to the bare TiO2. Finally, the effect of the scavengers was investigated by to be the most reactive species, and the mechanism of the enhancement was suggested for investigation of the proposed structures in various photo‐catalytic and biomedical applications.