The structure of N-[3-phenyl-5-(1,2,3,4-oxatriazolio)]-phenylamide at 105 K

The crystal and molecular structure of the meso-ionic title compound, C13H10N4O, have been determined by X-ray methods using 2667 reflections above background level collected by counter methods at 105 K. The crystals are monoclinic, space group P2a/c, with cell dimensions: a=5.233(2) A; b=18.846(6) A; c=11.643(2) A, beta=105.71 degrees(2), with 4 molecules per unit cell. The structure model was refined to an R-factor of 0.047. In order to reduce the influence of the valence electrons all reflections with sin theta/lambda smaller than 0.5 A- minus 1 were excluded in the last stages of the refinement procedure (leaving 1658 Fo'S, R=0.058). The central five-membered ring is found to be planar and the bond lengths within this ring indicate a resonance stabilized system, as has been found for sydnones. The planes of the two benzene rings are tilted 11.7 and 8.0 degrees, respectively, with respect to the plane of the central oxatriazolio-ring.?