Crystal and molecular structure of 3-p-bromophenyl-1-nitroso-2-pyrazoline

Abstract

The bromoderivative of product C₉H₉N₃O, obtained when diazomethane is reacted with benzonitrile oxide in ehter, has been examined by X-ray single-crystal techniques and shown to have the structure of 3-p-bromophenyl-1-nitroso-2-pyrazoline. The crystas are monoclinic with space group P2₁/c and a=5.636 ± 0.012, b=9.775 ± 0.021, c= 17.516 ± 0.031 Å, β=97.45 ± 0.2°. The final R index with all the non-hydrogen atoms anisotropically refined is 0.094 for 1075 visually estimated intensities. The molecule is slightly but significantly non-planar. The structure is stabilized mainly by van der Waala interactions; however, a short Br … O of length 3.298 Å, which is slightly less than the expected van der Waals separation, suggests that weak charge transfer interaction may be present. The C-Br…O angle is 176.1°.