Ottersen T, Christophersen C, Treppendahl S
Acta Chem Scand A. 1975;29(1):45-50. doi: 10.3891/acta.chem.scand.29a-0045.
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.?
已通过X射线方法，在105 K下用计数器方法收集了2667个高于背景水平的反射，测定了内消旋离子型标题化合物C₁₃H₁₀N₄O的晶体和分子结构。晶体为单斜晶系，空间群P2₁/c，晶胞参数：a = 5.233(2) Å；b = 18.846(6) Å；c = 11.643(2) Å，β = 105.71°(2)，每个晶胞中有4个分子。结构模型精修后的R因子为0.047。为了减少价电子的影响，在精修过程的最后阶段排除了所有sin θ/λ小于0.5 Å⁻¹的反射（剩下1658个F₀值，R = 0.058）。发现中心五元环是平面的，该环内的键长表明是一个共振稳定体系，如同在烯二酮中所发现的那样。两个苯环的平面相对于中心恶二唑啉环的平面分别倾斜11.7°和8.0°。
