The crystal and molecular structure of a new heterocycle: 1,2-dibromo-1,2-diphenyl-1,2-dihydroazeto[1,2-a]pyridinium chlorate

Abstract

The structure of the title compound, representative of the hitherto unknown dihydroazeto[1,2-a]pyridinium ring system, has been determined by a three-dimensional X-ray analysis. Orthorhombic crystals in space group Fdd2 have lattice parameters a= 12.18(1), b= 17.34(2), c= 18.72(2)Å for Z= 8. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to R 0.0547 for 1 039 reflections. The molecular cation lies across a two-fold axis which gives rise to a disorder of the bridgehead atoms. The heterocycle has all its atoms nearly coplanar, with the four-membered ring trapezoidally distorted having the shortest and longest sides 1.37(2) and 1.59(2)Å, respectively.