Syntheses,Crystal Structures,and Antimicrobial Activities of 3-Bromo-N＇-（2- chloro-5-nitrobenzylidene）benzohydrazide and 3-Bromo-N＇-（4-nitrobenzylidene）benzohydrazide

Two new hydrazone compounds, 3-bromo-N'-(2-chloro-5-nitrobenzylidene)-ben- zohydrazide 1 and 3-bromo-N'-(4-nitrobenzylidene)benzohydrazide 2, have been synthesized and characterized by elemental analysis, IR spectra, 1H NMR, and single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P21/c with a=7.7924(10), b=24.490(3), c=7.8989(9) , β=94.987(6)°, V=1501.7(3) 3, Z=4, R=0.0345 and wR=0.0739. Compound 2 crystallizes in monoclinic, space group P21/c with a=7.4099(11), b=24.868(4), c=8.3255(12) , β=112.796(8)°, V=1414.3(4) 3, Z=4, R=0.0744 and wR=0.1912. Both compounds display E configurations with respect to the C=N double bonds. In the crystal structure of 1, molecules are linked through N-H…N and N-H…O hydrogen bonds, forming chains running along the c axis. In the crystal structure of 2, molecules are linked through N-H…O hydrogen bonds, forming chains running along the c axis. The preliminary antimicrobial activities were studied.