The crystal and molecular structure of a compound containing a novel ring system:(E)-6-(bromomethylene)-5,6-dihydro-4,4-dimethyl-2-phenyl-4H-1,3,4-oxadiazinium bromide

Abstract

The crystal structure of (E)-6-(bromomethylene)-5,6-dihydro-4,4-dimethyl-2-phenyl-4H-1,3,4-oxadiazinium bromide has been determined by single crystal X-ray diffraction methods. The crystals are monoclinic, space group P21/c, with a = 12.002(5), b = 6.414(4), c = 17.881(7) Å, β = 101.42(7)°, and Z = 4 formula units of C12H14N2OBr2. The structure was refined by full-matrix least-squares analysis to a conventional R-factor of 0.0491 for 1019 observed reflections. The oxadiazinium ring is in the half-chair form, with the methylene group out of the plane defined by the other five atoms. The C—O bond distances in the ring are somewhat shorter than the distance observed for a carbon–oxygen single bond, suggesting that some delocalization of electron density occurs over part of the ring.