Two New Schiff Bases Based on 5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde: Syntheses, Crystal Structures and Properties

Two new Schiff bases based on 5-chloro-3-methyl-l-phenyl-1H-pyrazole-4-carb aldehyde, namely, N-((5-chloro-3-methyl-1-pheny1-1H-pyrazol-4-yl)methylene)-4-morpholino aniline (IIIa) and N-(5-chloro-3-methyl-l-phenyl-lH-pyrazol-4-y1)methylene)-3-fluoro-4-morpholinoaniline (IIIb), were synthesized and characterized by IR, LC-MS, H-1 NMR and C-13 NMR spectroscopy. Meanwhile, the three-dimensional configurations of the two title compounds were further characterized by single-crystal X-ray diffraction analyses. Both the compounds are thermodynamically stable trans-isomers. Moreover, the fluorescence properties and antioxidant activities against DPPH of the two target compounds have been investigated, and the results showed that the title compounds both have fluorescence performance and certain antioxidant activities against DPPH radical.